Objective:To investigate the effects of gelatin methacrylate anhydride (GelMA) hydrogel loaded with small extracellular vesicles derived from human umbilical cord mesenchymal stem cells (hUCMSCs-sEVs) in the treatment of full-thickness skin defect wounds in mice.Methods:This study was an experimental study. hUCMSCs-sEVs were extracted by ultracentrifugation, their morphology was observed through transmission electron microscope, and the expression of CD9, CD63, tumor susceptibility gene 101 (TSG101), and calnexin was detected by Western blotting. The human umbilical vein endothelial cells (HUVECs), the 3 rd and 4 th passages of human epidermal keratinocytes (HEKs) and human dermal fibroblasts (HDFs) were all divided into blank control group (routinely cultured) and hUCMSC-sEV group (cultured with the cell supernatant containing hUCMSCs-sEVs). The cell scratch test was performed and the cell migration rates at 6, 12, and 24 h after scratching were calculated, the cell Transwell assay was performed and the number of migration cells at 12 h after culture was calculated, and the proportion of proliferating cells was detected by 5-acetylidene-2'-deoxyuridine and Hoechst staining at 24 h after culture, with sample numbers being all 3. The simple GelMA hydrogel and the GelMA hydrogel loaded with hUCMSCs-sEVs (hereinafter referred to as hUCMSC-sEV/GelMA hydrogel) were prepared. Then the micromorphology of 2 kinds of hydrogels was observed under scanning electron microscope, the distribution of hUCMSCs-sEVs was observed by laser scanning confocal microscope, and the cumulative release rates of hUCMSCs-sEVs at 0 (immediately), 2, 4, 6, 8, 10, and 12 d after soaking hUCMSC-sEV/GelMA hydrogel in phosphate buffer solution (PBS) were measured and calculated by protein colorimetric quantification ( n=3). Twenty-four 6-week-old male C57BL/6J mice were divided into PBS group, hUCMSC-sEV alone group, GelMA hydrogel alone group, and hUCMSC-sEV/GelMA hydrogel group according to the random number table, with 6 mice in each group, and after the full-thickness skin defect wounds on the back of mice in each group were produced, the wounds were performed with PBS injection, hUCMSC-sEV suspenson injection, simple GelMA coverage, and hUCMSC-sEV/GelMA hydrogel coverage, respectively. Wound healing was observed on post injury day (PID) 0 (immediately), 4, 8, and 12, and the wound healing rates on PID 4, 8, and 12 were calculated, and the wound tissue was collected on PID 12 for hematoxylin-eosin staining to observe the structure of new tissue, with sample numbers being both 6. Results:The extracted hUCMSCs-sEVs showed a cup-shaped structure and expressed CD9, CD63, and TSG101, but barely expressed calnexin. At 6, 12, and 24 h after scratching, the migration rates of HEKs (with t values of 25.94, 20.98, and 20.04, respectively), HDFs (with t values of 3.18, 5.68, and 4.28, respectively), and HUVECs (with t values of 4.32, 19.33, and 4.00, respectively) in hUCMSC-sEV group were significantly higher than those in blank control group ( P<0.05). At 12 h after culture, the numbers of migrated HEKs, HDFs, and HUVECs in hUCMSC-sEV group were 550 ±23, 235 ±9, and 856 ±35, respectively, which were significantly higher than 188 ±14, 97 ±6, and 370 ±32 in blank control group (with t values of 22.95, 23.13, and 17.84, respectively , P<0.05). At 24 h after culture, the proportions of proliferating cells of HEKs, HDFs, and HUVECs in hUCMSC-sEV group were significantly higher than those in blank control group (with t values of 22.00, 13.82, and 32.32, respectively, P<0.05). The inside of simple GelMA hydrogel showed a loose and porous sponge-like structure, and hUCMSCs-sEVs was not observed in it. The hUCMSC-sEV/GelMA hydrogel had the same sponge-like structure, and hUCMSCs-sEVs were uniformly distributed in clumps. The cumulative release rate curve of hUCMSCs-sEVs from hUCMSC-sEV/GelMA hydrogel tended to plateau at 2 d after soaking, and the cumulative release rate of hUCMSCs-sEVs was (59.2±1.8)% at 12 d after soaking. From PID 0 to 12, the wound areas of mice in the 4 groups gradually decreased. On PID 4, 8, and 12, the wound healing rates of mice in hUCMSC-sEV/GelMA hydrogel group were significantly higher than those in the other 3 groups ( P<0.05); the wound healing rates of mice in GelMA hydrogel alone group and hUCMSC-sEV alone group were significantly higher than those in PBS group ( P<0.05). On PID 8 and 12, the wound healing rates of mice in hUCMSC-sEV alone group were significantly higher than those in GelMA hydrogel alone group ( P<0.05). On PID 12, the wounds of mice in hUCMSC-sEV/GelMA hydrogel group showed the best wound epithelization, loose and orderly arrangement of dermal collagen, and the least number of inflammatory cells, while the dense arrangement of dermal collagen and varying degrees of inflammatory cell infiltration were observed in the wounds of mice in the other 3 groups. Conclusions:hUCMSCs-sEVs can promote the migration and proliferation of HEKs, HDFs, and HUVECs which are related to skin wound healing, and slowly release in GelMA hydrogel. The hUCMSC-sEV/GelMA hydrogel as a wound dressing can significantly improve the healing speed of full-thickness skin defect wounds in mice.

Objective:To explore the changes in entero-insular axis function and its role in mice with severe burns.Methods:This study was an experimental study. Ninety C57BL/6J male mice aged 8-10 weeks were divided into sham injury group and burn group (with 45 mice in each group) according to the random number table. A full-thickness scald (hereinafter referred to as burn) wound of 30% of the total body surface area was created on the back of mice in burn group, and the mice in sham injury group were simulated to cause a sham injury. Twenty-four hours after injury, the fasting blood glucose was measured ( n=12), followed by intraperitoneal glucose tolerance test and oral glucose tolerance test; the curve of blood glucose concentration changes over time was plotted, and the area under the curve was calculated ( n=6); the blood was taken from the heart before intraperitoneal injection or gavage of glucose solution and at 30, 60, and 120 minutes after intraperitoneal injection or gavage of glucose solution for measuring the plasma insulin and glucagon like peptide-1 (GLP-1) levels using enzyme-linked immunosorbent assay (ELISA), with a sample number of 3; the ileal tissue was taken from 3 mice in each group for detecting the GLP-1 expression and apoptosis levels of intestinal L cells by immunofluorescence staining and TdT-mediated dUTP nick-end labeling staining; the pancreatic islets were collected from 6 mice in each group for glucose-stimulated insulin secretion experiments. After incubation with low glucose (2.8 mmol/L glucose) and high glucose (16.7 mmol/L glucose), the supernatant was taken and the insulin level was detected using ELISA. Thirty-six C57BL/6J male mice aged 8-10 weeks were divided into sham injury group, burn group, and burn+exendin-4 (Ex-4) group (with 12 mice in each group) according to the random number table. The mice in sham injury group and burn group were subjected to the same corresponding treatment as before. The mice in burn+Ex-4 group were injured in the same way as the burn group mice followed by treatment with GLP-1 receptor agonist Ex-4. Twenty-four hours after injury, mouse pancreatic islets were collected, the protein expressions of heavy-chain binding protein (BIP), protein kinase R-like endoplasmic reticulum kinase (PERK), phosphorylated PERK (p-PERK), eukaryotic translation initiation factor 2α (eIF2α), phosphorylated eIF2α (p-eIF2α), and CCAAT/enhancer-binding protein homologous protein (CHOP) were detected using Western blotting, and the p-PERK/PERK and p-eIF2α/eIF2α ratios were calculated ( n=3), the apoptosis rate of pancreatic islet cells was detected using flow cytometry ( n=3), the glucose stimulated insulin secretion experiment was conducted as before to detect insulin levels in the supernatant ( n=6). Results:Twenty-four hours after injury, the fasting blood glucose of mice in burn group was (7.3±1.0) mmol/L, which was significantly higher than (5.1±0.6) mmol/L in sham injury group ( t=6.36, P<0.05). Twenty-four hours after injury, in the intraperitoneal glucose tolerance test and oral glucose tolerance test, the areas under the curve of blood glucose concentration changes over time of mice in burn group were significantly larger than those in sham injury group (with t values of 4.32 and 6.03, respectively, P<0.05); compared with those in sham injury group, the plasma insulin levels of mice before intraperitoneal injection of glucose solution and the plasma GLP-1 levels of mice before intraperitoneal injection or gavage of glucose solution in burn group were significantly decreased ( P<0.05), and the plasma levels of insulin of mice at 30, 60, and 120 minutes after intraperitoneal injection or gavage of glucose solution, as well as the plasma levels of GLP-1 of mice at 30 and 60 minutes after gavage of glucose solution were significantly decreased in burn group ( P<0.05). Twenty-four hours after injury, compared with those in sham injury group, the GLP-1 expression level of intestinal L cells of mice in burn group was significantly decreased ( t=7.74, P<0.05), and the apoptosis level was significantly increased ( t=14.28, P<0.05). Twenty-four hours after injury, the insulin level in the supernatant of mice pancreatic islet incubated with high glucose in burn group was (8.5±0.4) ng/mg, which was significantly lower than (15.7±0.3) ng/mg in sham injury group ( t=18.68, P<0.05). Twenty-four hours after injury, compared with those in sham injury group, the protein expression levels of BIP, p-PERK/PERK, p-eIF2α/eIF2α, and CHOP in the pancreatic islets of mice in burn group were significantly increased ( P<0.05); compared with those in burn group, the protein expression levels of BIP, p-PERK/PERK, p-eIF2α/eIF2α, and CHOP in the pancreatic islets of mice in burn+Ex-4 group were significantly decreased ( P<0.05). Twenty-four hours after injury, the apoptosis rate of pancreatic islet cells of mice in burn group was (32.0±3.0)%, which was significantly higher than (10.3±2.5)% in sham injury group ( P<0.05); the apoptosis rate of pancreatic islet cells of mice in burn+Ex-4 group was (20.0±3.6)%, which was significantly lower than that in burn group ( P<0.05). Twenty-four hours after injury, the insulin level in the supernatant of mice pancreatic islet incubated with high glucose in burn group was significantly lower than that in sham injury group ( P<0.05), while the insulin level in the supernatant of mice pancreatic islet incubated with high glucose in burn+Ex-4 group was significantly higher than that in burn group ( P<0.05). Conclusions:After severe burns, the mice display dysfunction of the entero-insular axis, increased apoptosis of intestinal L cells, decreased synthesis and secretion of GLP-1, endoplasmic reticulum stress and increased apoptosis in pancreatic islet cells and a decrease in glucose-stimulated insulin secretion. The GLP-1 receptor agonist Ex-4 can protect the function of pancreatic islet cells of mice with severe burns, reducing the apoptosis level of pancreatic islet cells and promoting insulin secretion possibly via the alleviation of endoplasmic reticulum stress.

ObjectiveTo investigate the possible mechanism of Wenfei Huaxian Decoction （温肺化纤汤） in treatment of pulmonary fibrosis in systemic sclerosis-associated interstitial lung disease （SSc-ILD）. MethodsSixty C3H/He female rats were randomly divided into a control group， a model group， a pirfenidone group， and low-， medium-， and high-dose Wenfei Huaxian Decoction groups. The SSc-ILD model mice was established by subcutaneous injection of bleomycin solution 0.04 mg/d into the back of mice for 28 days in all groups but the control group. After successful modelling， the pirfenidone group was given pirfenidone capsule 300 mg/（kg·d） by gavage， the low-， medium- and high-dose Wenfei Huaxian Decoction groups were given Wenfei Huaxian Decoction 7.81， 15.62， and 31.24 g/（kg·d） by gavage， respectively， and the control group as well as the model group were given normal saline 0.1 ml/10 g by gavage， for a total of 21 days. At the end of the intervention， HE staining and Masson staining were used to observe the pathological changes in the skin and lung tissues； the hydroxyproline content of the skin and lung tissues was detected； the protein expression levels of endoplasmic reticulum stress-related proteins glucose-regulated protein 78 （BIP） and C/EBP homologous protein （CHOP） as well as those of nuclear factor kappa B （NF-κB） pathway p65 were measured by western blot； ELISA was performed to determine the expression levels of interferon gamma （IFN-γ）， interleukin 6 （IL-6） and tumour necrosis factor alpha （TNF-α） in serum of rats. ResultsThe results of HE and Masson staining indicated that compared with the control group， the dermis significantly thickened， the number of collagen fibers significantly enlarged， and the number of inflammatory cells significantly increased in the model group； the lung tissue showed a marked inflammatory cellular response with massive collagen fibre proliferation with inflammatory cell infiltration. Compared with the model group， the skin tissue and lung tissue collagen fibre proliferation significantly reduced and inflammatory cell infiltration reduced in the pirfenidone group and all dose groups of Wenfei Huaxian Decoction， and the effects of pirfenidone group and Wenfei Huaxian Decoction medium- and high-dose groups were basically comparable. Compared with the model group， the content of hydroxyproline in skin and lung tissue， the serum level of IFN-γ， IL-6 and TNF-α， and the expression levels of BIP and CHOP protein in lung tissue increased in model group （P＜0.05）. Compared with model group， the content of hydroxyproline in skin tissue of pirfenidone group， low-and medium-dose Wenfei Huaxian Decoction groups decreased， and the content of hydroxyproline in lung tissue of medium-dose Wenfei Huaxian Decoction group decreased. The serum level of IFN-γ， IL-6， TNF-α and the expression levels of BIP， CHOP and p65 protein in lung tissue of rats in pirfenidone group and high-dose Wenfei Huaxian Decoction group decreased （P＜0.05）. The content of hydroxyproline in lung tissue of medium-dose Wenfei Huaxian Decoction group was significantly lower than that of low-dose and high-dose Wenfei Huaxian Decoction group， and the serum level of IFN-γ， IL-6， TNF-α in low- and medium-dose Wenfei Huaxian Decoction group were higher than those in high-dose Wenfei Huaxian Decoction group. The expression level of BIP protein in high-dose group was significantly lower than that in low- and medium-dose Wenfei Huaxian Decoction groups （P＜0.05）. ConclusionWenfei Huaxian Decoction can improve the skin and lung fibrosis of SSc-ILD rats， which may act through anti-inflammation， inhibition of NF-κB pathway， and then inhibition of endoplasmic reticulum stress， which ultimately blocked the fibrotic process.

BACKGROUND:Lingual movable wing is a new type of lingual orthodontic technique and the different stretching lengths of the wring affect the torque control effect of anterior teeth.However,there is yet no related biomechanical research. OBJECTIVE:To investigate the displacement trend of dentition during adduction of mandibular anterior teeth and the effect of different wing stretching lengths on the biomechanical effect of mandibular anterior teeth. METHODS:The data of the mandible and lower dentition were collected by cone-beam CT and reconstructed using Mimics software to establish a three-dimensional finite element model of mandibular anterior teeth adducted by the lingual movable wing.The ANSYS software was used to analyze the initial displacement of the mandibular anterior teeth under the following conditions:A,2 mm stretching length;B,2.5 mm stretching length;C,3 mm stretching length;and D,3.5 mm stretching length. RESULTS AND CONCLUSION:The trend of initial displacement of lower dentition:The central incisors moved lingually with depression,the lateral incisors and canines moved mildly lingually with mesial lingual torsion,the second premolar was tilted distally with a marked lingual inclination and the first molar showed an overall mesial inclination with mesial crown eversion.Therefore,in the adduction cases of mandibular tooth extraction,attention should be paid to the lingual movement of the second premolar,which could be offset by corresponding techniques in clinic.The trend of anterior tooth displacement in all directions:from condition A to condition D,in the sagittal direction,the difference value in crown-root displacement of central incisors changed from-11.891 μm to-5.757 4 μm,indicating that the central incisor changes from oblique movement to overall movement.The difference value in crown-root displacement of lateral incisors changed from-11.828 1 μm to-6.711 45 μm,and that of canines changed from-7.572 3 μm to-4.695 5 μm,indicating that the oblique movement of the lateral incisors and canines is also changing to an overall movement.In the vertical direction,from condition A to condition D,the reduction of incisors was gradually increased,while that of canines was gradually decreased.These findings indicate that the stretching length of the wing can affect the oblique movement trend of the anterior teeth.As the wing continues to stretch,the torque control of the lower anterior teeth will become better.

Objective:Proximal femur tumor resection often leads to hip joint instability and functional loss.Various methods have been clinically applied to repair hip joint soft tissue function,but deficiencies remain.This study aims to evaluate the advantages and disadvantages of the ligament advanced reinforcement system(LARS)tumor tube in assisting soft tissue function reconstruction in patients undergoing tumor type artificial hip replacement surgery. Methods:This study included 85 patients(41 males,44 females)with proximal femoral tumors treated at the Xiangya Bone Tumor Treatment Center from January 2012 to January 2022,aged 10 to 79(38.5±18.2)years.Among them,13 cases had benign aggressive tumors,45 had primary malignant bone tumors,and 27 had bone metastases.Clinical data,imaging data,and intraoperative photos were collected.Patients were followed up and postoperative functional evaluations were conducted using the Musculoskeletal Tumor Society(MSTS)scoring system and Harris hip joint scoring system to assess limb function and hip joint function. Results:Preoperative pathological fractures were present in 37 cases(43.5％),with a lesion length of(9.4±2.9)cm.Among non-metastatic tumor patients,7 experienced postoperative recurrence,including 6 cases of osteosarcoma and 1 case of fibrosarcoma.Pulmonary metastases occurred in 9 osteosarcoma patients.Five patients required reoperation due to postoperative complications,including 3 cases of deep vein thrombosis,1 case of giant cell granuloma,and 1 case of prosthesis infection.Postoperatively,5 patients exhibited Trendelenburg gait,and 6 had leg length discrepancies.The postoperative MSTS score was 26.7±1.4,and the Harris score was 89.6±5.3. Conclusion:The LARS tumor tube can effectively assist in reconstructing the soft tissue function of the hip joint and greatly reduce postoperative complications,making it an effective technical improvement in joint function reconstruction in tumor type artificial hip replacement surgery.

Objective: To explore the relationship between maternal emotional symptoms and emotional and behavioral problems (EBPs) of preschool offspring, and to provide reference for prevention and intervention of emotional and behavior problems in preschool children. Methods: A total of 4 100 preschool children aged 3-6 in Fuyang City were enrolled by stratified cluster sampling method in June 2021. The Strengths and Difficulties Questionnaire (SDQ) and Depression Anxiety and Stress Scale (DASS-21) were used to investigate preschool children s EBPs and maternal emotional symptoms, respectively. Results: The detection rates of preschool children s emotional symptoms, conduct problems, hyperactivity, peer interaction problems, prosocial behavior and difficulty scores were 15.7%, 17.4%, 20.0%, 32.3%, 15.1% and 15.8%, respectively. The detection rates of mother s depression, anxiety and stress symptoms were 7.9%, 12.7% and 4.8%, respectively. Multivariate Logistic regression analysis showed that, compared with children of mothers with no depression, anxiety and stress symptoms, offspring of mothers reported depression, anxiety and stress symptoms had significantly higher risks of emotional symptoms, conduct problems, hyperactivity, peer problems and total difficulties ( OR=1.76-6.35, P <0.01). Maternal emotional symptoms had the most significant effect on children s emotional symptoms, and there was no significant correlation between maternal stress symptoms and children s prosocial behavior ( OR=1.40, P >0.05). There was no significant gender difference in the relationship between maternal emotional symptoms and children s emotional and behavioral problems ( ROR=0.73-1.07, P >0.05). For only children whose mothers reported stress symptoms showed a higher risk of emotional and behavior problems than non singleton children ( ROR=2.03, P <0.05). Conclusion Maternal emotional symptoms are related to preschool children s emotional and behavioral problems. Early identification and intervention of mother s negative emotional symptoms, are beneficial to the prevention of preschool children s emotional and behavioral problems.

Objective:To assess the risk of venous thromboembolism (VTE) and anticoagulation-related bleeding of acute critical emergency patients staying in the emergency department at least 72 h, so as to improve the ability of emergency physicians to identify risk factors of VTE and their awareness of safety prevention in these patients.Methods:Multicenter emergency internal medicine patients meeting the inclusion criteria at the same time were collected. Padua and Caprini scores were used to evaluate the risk of VTE and the HAS-BLED score was used to assess the risk of anticoagulation-related bleeding.Results:A total of 930 emergency patients from 7 medical centers were enrolled in our study from January 15, 2021 to March 15, 2021. The proportion of high-risk population with VTE was 50.22% with Padua score and 78.49% with Caprini score, respectively. The proportion of high-risk bleeding (HAS-BLED score) was 40.43%.Conclusions:More than half of the acute critical ill patients who stay in emergency department for more than 72 h are at high risk of VTE. This group of patients have a relatively low risk of anticoagulation-related bleeding.

Objective:To understand the current situation of spiritual nursing needs in elderly patients with primary glaucoma and its influencing factors, and to analyze its relationship with self-perceived burden and perceived social support, so as to provide a theoretical basis for reducing their spiritual distress and pain and meeting their spiritual nursing needs.Methods:A total of 218 elderly patients with primary glaucoma who were hospitalized in the department of ophthalmology of the First Hospital of Jilin University from March to September, 2022 were selected by convenience sampling. They were investigated by using general information questionnaire, the Nurse Spiritual Therapeutics Scale, the Self-Perceived Burden Scale, and the Perceived Social Support Scale. And multiple linear regression was used to analyze the influencing factors of spiritual nursing needs among elderly patients with primary glaucoma.Results:The total score of spiritual nursing needs of elderly patients with primary glaucoma was (30.73 ± 4.85). The highest dimension of item average score was "building a good atmosphere" (3.02 ± 0.59), and the lowest dimension was "helping religious practice" (1.95 ± 0.63). The total scores of spiritual nursing needs and self-perceived burden were negatively correlated ( r=-0.423, P<0.01), and positively correlated with the total scores of perceived social support ( r=0.515, P<0.01). Multivariate linear regression analysis showed that age, religious belief, educational level, treatment duration, residence, self-perceived burden, and perceived social support were the main influencing factors of spiritual care needs of elderly patients with primary glaucoma, ( t values were -5.23-7.04, all P<0.01), which could explain 44.5% of the total variation. Conclusions:The spiritual nursing needs of elderly patients with primary glaucoma were at a medium level. Therefore, it is recommended that nurses should carry out targeted spiritual nursing for them according to the differences and characteristics of different patients, to reduce their self-perceived burden, and to improve perceived social support level, in order to meet their spiritual nursing needs.

Objective:To investigate the allocation of nursing human resources in burn centers in China.Methods:A cross-sectional survey was conducted. Using a self-designed questionnaire, a survey was carried out from January to March 2022 to investigate the January to December 2021 status of 39 burn centers in China that met the inclusion criteria based on six strategic regions and other regions, including the hospital grade and the region, the number of nurses and opening beds in the burn centers and burn intensive care units (BICUs), the age, working seniority in burn specialty, educational background, professional title, personnel employment, and turnover of nurses and training of newly recruited nurses in the burn centers.Results:This survey covered 30 provinces, municipalities, and autonomous regions in China (excluding Hong Kong Special Administrative Region, Macao Special Administrative Region, and Taiwan region of China). A total of 39 questionnaires were collected, all of which were valid. The 39 burn centers were located in 38 tertiary A hospitals and 1 tertiary B hospital, with 26 burn centers in strategic areas. The nurse/bed ratio of burn centers in the Greater Bay Area of Guangdong, Hong Kong, and Macao was the highest, while the nurse/bed ratio of burn centers in border ethnic minority area was the lowest. Except for the Chengdu-Chongqing Economic Circle, BICUs had been set up in burn centers in other regions. Among the 39 burn centers, the percentage of nurses aged 25 to 34 years was 51.21% (738/1 441), the percentage of nurses worked in burn specialty for less than 5 years was 31.16% (449/1 441), the percentage of nurses with bachelor's degree was 69.74% (1 005/1 441), and the percentage of nurses with nursing professional title was 44.14% (636/1 441), which were the highest. There were significant differences in the employment of nurses, the percentage of permanent nurses in burn centers in the collaborative development zone of Beijing-Tianjin-Hebei was 82.48% (113/137), while the percentage of permanent nurses in burn centers in important military strategic area was only 9.42% (34/361); the turnover rate of nurses was 9.03% (143/1 584), among which the turnover rate of nurses was 18.14% (80/441) in burn centers in important military strategic area. The training for newly recruited nurses in 39 burn centers was mainly based on the guidance of senior nurses and the pre-job education+specialist training.Conclusions:The burn nursing human resources in strategic areas in China are seriously insufficient and unevenly distributed, with unstable nurse team and lack of standardized specialist training. In particular, the nursing human resources in BICUs need to be equipped and supplemented urgently.

Objective:To explore the mechanism of early pancreatic exocrine function changes in severely scalded rats.Methods:The experimental research methods was used. Eighty male Sprague-Dawley rats aged 7-8 weeks were divided into simple sham injury group ( n=8), sham injury+cholecystokinin octapeptide (CCK8) group ( n=8), severe scald+CCK8 group ( n=32), and extremely severe scald+CCK8 group ( n=32) by the random number table, which were treated accordingly. Immediately after injury of rats in the 2 sham injury groups and 1, 2, 3, and 7 days after injury of rats in the 2 scald groups, the improved methods including pancreatic duct puncture and catheterization were used to dynamically collect the pancreatic-bile juice (PBJ) of rats. The PBJ secretory volume within 1 h was recorded, and the content of pancreatic lipase, α-amylase, and trypsin in PBJ was detected by enzyme-linked immunosorbent assay (ELISA), and the number of samples was 8. The femoral venous blood was collected, and the concentrations of pancreatic lipase and α-amylase in serum were detected by standard colorimetry to reflect their activity ( n=8). The pancreatic tissue was extracted, and the levels of interleukin-1β (IL-1β) and IL-6 in pancreatic tissue were detected by ELISA ( n=8), the expression of hypoxia-inducible factor 1α (HIF-1α) in pancreatic tissue was detected by immunofluorescence method, and the histopathological changes in pancreatic tissue were observed by hematoxylin-eosin staining, the severity of pancreatic tissue injury in the 2 scald groups was evaluated by modified Schmidt method ( n=6), and the ultrastructure of acinar cells in pancreatic tissue was observed by transmission electron microscopy. Data were statistically analyzed with analysis of variance for factorial design, Tukey test, independent sample t test, and least significant difference test. Results:Compared with the PBJ secretory volume (0.740±0.030) mL in the pancreatic tissue of rats in simple sham injury group within 1 h immediately after injury, the (0.823±0.033) mL in sham injury+CCK8 group was significantly increased ( t=4.92, P<0.05). Compared with that of rats in sham injury+CCK8 group immediately after injury, the PBJ secretory volume of rats within 1 h in severe scald+CCK8 group ((0.681±0.024), (0.608±0.056), (0.525±0.025), and (0.720±0.044) mL) and extremely severe scald+CCK8 group ((0.540±0.025), (0.406±0.021), (0.475±0.036), and (0.690±0.018) mL) was significantly decreased on 1, 2, 3, and 7 days after injury ( P<0.05). Compared with that in severe scald+CCK8 group, the PBJ secretory volume of rats within 1 h in extremely severe scald+CCK8 group was significantly decreased on 1 and 2 days after injury ( P<0.05). Compared with that of rats in simple sham injury group immediately after injury, the content of pancreatic lipase, α-amylase, and trypsin in PBJ of rats in sham injury+CCK8 group immediately after injury was significantly increased (with t values of 4.56, 3.30, and 4.99, respectively, P<0.05). Compared with that of rats in sham injury+CCK8 group immediately after injury, the content of pancreatic lipase and α-amylase in PBJ of rats in severe scald+CCK8 group and extremely severe scald+CCK8 group was significantly decreased on 1, 2, 3, and 7 days after injury ( P<0.05), the trypsin content in PBJ of rats in extremely severe scald+CCK8 group was significantly decreased on 2 days after injury ( P<0.05). Compared with that in severe scald+CCK8 group, the content of pancreatic lipase in PBJ of rats in extremely severe scald+CCK8 group was significantly decreased on 1, 2, and 3 days after injury ( P<0.05), and the content of α-amylase and trypsin in PBJ was significantly decreased on 1 and 2 days after injury ( P<0.05). There were no statistically significant differences in the activities of pancreatic lipase and α-amylase in serum of rats among the 4 groups at various time points after injury ( P>0.05). Compared with that of rats in sham injury+CCK8 group immediately after injury, the levels of IL-1β in pancreatic tissue of rats in severe scald+CCK8 group on 1, 2, and 3 days after injury and in extremely severe scald+CCK8 group on 1, 2, 3, and 7 days after injury were significantly increased ( P<0.05), and the levels of IL-6 in pancreatic tissue of rats in severe scald+CCK8 group and extremely severe scald+CCK8 group were significantly increased on 1, 2, 3, and 7 days after injury ( P<0.05). Compared with that in severe scald+CCK8 group, the IL-1β level in pancreatic tissue of rats in extremely severe scald+CCK8 group was significantly increased on 2 and 3 days after injury ( P<0.05), and IL-6 level in pancreatic tissue was significantly increased on 2 days after injury ( P<0.05). The expression levels of HIF-1α in pancreatic tissue of rats in simple sham injury group and sham injury+CCK8 group immediately after injury were lower; and compared with that in sham injury+CCK8 group immediately after injury, the expression levels of HIF-1α in pancreatic tissue of rats in the 2 scald groups increased to a certain extent at different time points after injury, and the expression position was transited from the edge of the pancreatic tissue to the whole pancreas, the expression levels of HIF-1α in pancreatic tissue of rats in the 2 scald groups tended to be normal on 7 days after injury. Compared with that in simple sham injury group immediately after injury, the proportion of acinar cell cytoplasm in pancreatic tissue of rats in sham injury+CCK8 group was increased; and with the increase of time after injury, edema, hemorrhage, necrosis, and inflammatory infiltration appeared in pancreatic tissue of rats in the 2 scald groups. Compared with that in severe scald+CCK8 group, the scores of edema, inflammatory cell infiltration, bleeding, and necrosis in pancreatic tissue of rats in extremely severe scald+CCK8 group were increased to varying degrees at various time points after injury, and the scores of pancreatic tissue of rats in the 2 scald groups basically recovered to normal on 7 days after injury. Compared with that in simple sham injury group immediately after injury, the number of enzyme granules in acinar cells of pancreatic tissue of rats in sham injury+CCK8 group was increased, and with the increase of time after injury, the enzyme granules in acinar cells of rats in the 2 scald groups were gradually reduced basically. Conclusions:The exocrine functions of pancreas, such as synthesis and secretion of pancreatic enzymes, are decreased in the early stage in severely scalded rats. And the greater the scalded area, the more significant the decline of pancreatic exocrine function. This change may be related to hypoxic injury and inflammation in pancreatic tissue after severe scald.