AIM: To observe the level of vascular endothelial growth factor (VEGF) secreted by monocytes cultured with electrical burn serum, and to explore the effect of VEGF on monocyte-endothelial cell adhesion.METH-ODS:The electrical burn serum of the rat was prepared.The normal serum from the rats without treating electric current was also collected for control.The contents of VEGF and its soluble receptor sFlt-1 in electrical burn group were determined by double-antibody sandwich ELISA.THP-1 cells were randomly divided into normal serum group and electrical burn serum group.The contents of VEGF and sFlt-1 in the culture supernatants were measured by double-antibody sandwich ELISA. THP-1 cells were also randomly divided into another 4 groups:normal serum group, electrical burn serum group, normal serum +inhibitor group and electrical burn serum +inhibitor group.THP-1 cells, which were incubated with the serum for 3 h and 6 h, were labeled with calcein-AM and then were added into the well with monolayer of endothelial cell line EA.hy926 to detect monocyte-endothelial cell adhesion.RESULTS:The levels of serum VEGF of the rats with electrical burns were significantly increased, the levels of serum sFlt-1 were significantly decreased as compared with the controls. The levels of VEGF secreted by THP-1 cells cultured with electrical burn serum were significantly increased, the levels of sFlt-1 were decreased correspondingly.Electrical burn serum enhanced monocyte-endothelial cell adhesion, sFlt-1 inhibi-ted the adhesion between monocytes and endothelial cells.CONCLUSION:The monocytes exposed to the electrical burn serum secrete VEGF, which enhance the adhesion between monocytes and endothelial cells.Blockage of VEGF activity may effectively inhibit monocyte-endothelial cell adhesion.

Objective To explore the diagnostic value of CT cerebral perfusion imaging on the brain injury of the high +Gx in Rhesus. Methods Seven healthy male adult Rhesus were randomly divided into control group and +15 Gx group. The +15 Gx group underwent parabolic G curve in animal centrifuge. The animals were all examined by CT cerebral perfusion before +Gx exposure, 2 h, 24 h, and 1 week after ~+Gx exposure. The results were compared with pathologic examination. Results 2 h and 24 h after +15 Gx exposure, brain ischemia was showed on CT cerebral perfusion imaging. After 1 week, the brain ischemia was almost recovered to normal. Mild ischemic atrophy was observed in pyramidal neurons in cerebral cortex by light microscopy. Electron microscopic observation showed chromatin marginating and mitochondria cristae blurring in pyramidal cells after +Gx overload. Conclusion High G from simulating spaceship emergency return can cause ischemic injuries of the brain in Rhesus, and CT brain perfusion imaging can provide valuable diagnostic information.

OBJECTIVETo explore the molecular mechanism of microRNA-21 in myocardial damage of rats in the early stage of severe scald injury by observing the expression of microRNA-21 and programmed cell death 4 (PDCD4) in myocardial tissue of rat and to validate the relationship between them in cell model.

METHODS(1) Forty SD rats were divided into sham injury group (n =8, sham injured) and scald injury group (n =32, inflicted with 30% TBSA full-thickness scald on the back) according to the random number table. The left ventricular tissue was collected from rats in sham injury group at post injury hour 1 without any fluid infusion. Rats in scald injury group were given an intraperitoneal injection of lactic acid Ringer's solution and 8 rats were respectively sacrificed at post injury hour 3, 6, 12, 24 to harvest left ventricular tissue. The expression of microRNA-21 in myocardial tissue was assessed by real-time fluorescent quantitative RT-PCR. The protein expression of PDCD4 in myocardial tissue was assessed by Western blotting. (2) Rat myocardial cell line H9C2 was divided into microRNA-21 inhibitor group (cells were transfected with microRNA-21 inhibitor) and negative transfection control group (cells were transfected with negative control of microRNA inhibitor) according to the random number table. At post transfection hour 48, real-time fluorescent quantitative RT-PCR and Western blotting were performed respectively to determine the mRNA and protein expression levels of PDCD4 in cells. Data were processed with one-way analysis of variance, LSD-t and two independent samples t test. The relationship between microRNA-21 expression and PDCD4 protein level in myocardial tissue of rats was assessed by linear correlation analysis.

RESULTS(1) The expression levels of microRNA-21 in myocardial tissue of rats in sham injury group at post injury hour 1 and in scald injury group at post injury hour 3, 6, 12, 24 were respectively 0. 96 ± 0. 13, 0. 44 ± 0. 08, 0. 42 ± 0. 10, 0.33 +0.07, and 0.61 0.10 (F = 27.331, P <0.001). Compared with that in myocardial tissue of rats in sham injury group at post injury hour 1, expression level of microRNA-21 was significantly decreased in scald injury group at post injury hour 3, 6, 12, 24 (with t values from 4. 558 to 9.410, P values below 0.01). The protein expression levels of PDCD4 in myocardial tissue of rats in sham injury group at post injury hour 1 and in scald injury group at post injury hour 3, 6, 12, 24 were respectively 0.44 ± 0.05, 0.60 ± 0.09, 0.92 ± 0. 15, 0. 86 ± 0.11, and 0.57 ± 0. 10 (F =8.622, P =0.003). Compared with that in sham injury group at post injury hour 1, protein expression level of PDCD4 was significantly increased in scald injury group at post injury hour 6 and 12 (with t values respectively 4. 968 and 4. 122, P values below 0.01). A significant negative correlation between the expression of microRNA-21 and PDCD4 protein in myocardial tissue of rats of scald injury group was observed at each time point (r = -0. 572, P = 0. 026). (2) The mRNA and protein expression levels of PDCD4 of myocardial cells in microRNA-21 inhibitor group were respectively 1.73 ± 0. 29 and 0. 38 ± 0. 08, which were significantly higher than those in negative transfection control group (0.95 ± 0.14 and 0.23 ± 0.03, with t values respectively 4. 857 and 3.356, P <0.05 or P <0.01).

CONCLUSIONSExpression of microRNA-21 was decreased, while expression of PDCD4 was increased, in myocardial tissue of rats in the early stage of severe scald injury. MicroRNA-21 might participate in myocardial damage in the early stage of scald injury by negatively regulating expression of PDCD4.

Animals ; Apoptosis Regulatory Proteins ; metabolism ; Blotting, Western ; Burns ; metabolism ; pathology ; MicroRNAs ; genetics ; metabolism ; Myocardium ; metabolism ; pathology ; Myocytes, Cardiac ; metabolism ; pathology ; Rats ; Reverse Transcriptase Polymerase Chain Reaction ; Soft Tissue Injuries

Objective: To explore the differential expression of microRNAs in the serum among patients with electrical burn or thermal burn and healthy persons and to explore the significance. Methods: In this study we included three patients with electrical burn and three patients with thermal burn, conforming to the inclusion criteria and hospitalized in our burn ward from June to August 2015, and three healthy adult volunteers. Their serum samples were separated from whole blood and divided into electrical burn group, thermal burn group, and normal control group. Total RNA was extracted from their serum samples using Trizol method. The differentially expressed microRNAs (with differential ratio larger than or equal to 2.000, less than or equal to 0.500) among the three groups were screened by microRNA chip technique. Then cluster and Venn diagram analysis of the differentially expressed microRNAs were performed. Enrichment analysis of Kyoto encyclopedia of genes and genomes (KEGG) signaling pathway was performed on the distinctly changed microRNAs (with differential ratio larger than or equal to 5.000, less than or equal to 0.500). Results: There were 220 differentially expressed microRNAs among serum of the three groups. MicroRNA expression profiles in serum of electrical burn and thermal burn groups were different from that in serum of normal control group. Compared with those in serum of normal control group, the expressions of 59 microRNAs changed more than 2.000 times in serum of electrical burn group, with 50 up-regulated microRNAs and 9 down-regulated microRNAs; the expressions of 40 microRNAs changed more than 2.000 times in serum of thermal burn group, with 21 up-regulated microRNAs and 19 down-regulated microRNAs. Compared with those in serum of thermal burn group, the expressions of 167 microRNAs changed more than 2.000 times in serum of electrical burn group. There were 17 exclusively expressed microRNAs in serum of thermal burn group and 26 exclusively expressed microRNAs in serum of electrical burn group, compared with those in serum of normal control group. Enrichment analysis of KEGG signaling pathway showed that compared with those in serum of normal control group, microRNAs which changed distinctly in serum of electrical burn group took part in the insulin secretion signaling pathway, arrhythmogenic right ventricular cardiomyopathy signaling pathway, hypertrophic cardiomyopathy signaling pathway, glutamatergic synapse signaling pathway, calcium signaling pathway, cyclic adenosine monophosphate signaling pathway, glycerophospholipid metabolism, pyrimidine metabolism, serotonergic synapse signaling pathway, etc, while microRNAs which changed distinctly in serum of thermal burn group took part in the tumor transcription misregulation signaling pathway, proteoglycans in tumor signaling pathway, microRNAs in tumor signaling pathway, long-term potentiation signaling pathway, citrate cycle signaling pathway, tumor necrosis factor signaling pathway, focal adhesion signaling pathway, endocytosis signaling pathway, insulin secretion signaling pathway, p53 signaling pathway, and estrogen signaling pathway, etc. Conclusions MicroRNA expression profiles in serum of electrical and thermal burn are different from that in serum of healthy adult. The signaling pathways enriched with target genes which are regulated by the differentially expressed microRNAs are related to the pathological changes and clinical manifestations after electrical or thermal burn.

Objective:To construct a risk prediction model for unplanned extubation (UEX) in postoperative patients, and to verify the predictive performance of the model.Methods:From January 2019 to April 2020, 314 patients who underwent surgy in Wuxi People's Hospital Affiliated to Nanjing Medical University and had postoperative indwelling catheters were selected by convenience sampling as the research object. The patients were divided into UEX group ( n=25) and non-UEX group ( n=289) according to whether UEX occurred postoperatively. The gender, age, admission to ICU, tracheal intubation, physical restraint, catheter number, analgesia, sedation, taking sleeping pills and postoperative fever of the two groups of patients were counted. Binomial Logistic regression was used to analyze the risk factors of postoperative UEX, and a risk prediction model was established. The area under the curve ( AUC) of receiver operating characteristic curve was used to test the predictive performance of the model. According to the same standard, the clinical data of 134 patients who underwent surgy from May to December 2020 were selected to validate the model. Results:The risk prediction model for UEX in postoperative patients finally included 3 risk factors, physical restraint, tracheal intubation, and age, and assigned 0-2, 0-4, and 0-5 respectively. The scores of the 3 indicators were summed up as a total score, with a total score of 0 to 11. The AUC was 0.887 [95% CI (0.807, 0.967) ] , the maximum Youden index was 0.591, the sensitivity was 0.640, the specificity was 0.951, and the predictive critical value was 5.5. The model validation showed that the sensitivity was 66.7%, the specificity was 92.6%, and the correct rate was 90.3%. Conclusions:The risk prediction model for UEX in postoperative patients has a good predictive performance, which can help clinical medical and nursing staff to quickly identify patients with high risk of UEX after surgery, and provide a reference for formulating targeted interventions.

Objective:To investigate the causes of death and etiological characteristics of skin tissue donors, and to provide reference for allogeneic skin transplantation.Methods:From October 2008 to October 2018, 49 skin tissue donors accepted by the Burn Department of Wuhan Third Hospital met the inclusion criteria of this study, and a cross-sectional study was conducted. According to the cause of death, the donors were divided into accidental death group (19 cases) and non-accidental death group (30 cases). The sex and death age of 49 donors were recorded, and the death age between different sex donors and that of donors between accidental death group and non-accidental death group were compared. Diseases or circumstances that caused the death of donors, hepatitis B, hepatitis C, acquired immunodeficiency syndrome, syphilis virus carrying status, and peripheral blood microbial culture results of 49 donors were recorded, and the detection of blood-borne infectious risk factors of donors between accidental death group and non-accidental death group was compared. Abnormal skin tissue was also selected during allogenic skin graft preparing for pathological examination. Data were statistically analyzed with Mann-Whitney U test and continuity correction chi-square test. Results:(1) Out of the 49 donors in this group, 38 were male (77.55%) and 11 were female (22.45%). The death age was 42.00 (24.00, 55.00) years, and the death age of male donors was similar to that of female donors ( Z=0.120, P>0.05). The death age of donors in accidental death group was lower than that in non-accidental death group, but the difference was not statistically significant ( Z=-1.581, P>0.05). (2) Among the causes and circumstances of the 49 donors in this group, there were 19 cases (38.78%) of injury, poisoning, and some other consequences of external causes, 11 cases (22.45%) of circulatory system diseases, 9 cases (18.37%) of tumors, 3 cases (6.12%) of nervous system diseases, 2 cases (4.08%) of respiratory system diseases, and 2 cases (4.08%) of congenital malformation, deformation, and chromosome abnormality, 1 case (2.04%) of blood and hematopoietic organ diseases and some diseases related to immune mechanism, 1 case (2.04%) of digestive system disease, and 1 case (2.04%) of genitourinary system disease. (3) There were 9 donors (18.37%) with blood-borne infectious risk factors among the 49 donors in this group, including 8 cases (16.33%) of blood-borne infectious diseases, which were 5 cases (10.20%) of hepatitis B, 2 cases (4.08%) of syphilis, and 1 case (2.04%) of hepatitis C, respectively. Blood microorganism culture was positive in 1 case (2.04%), in which multi-drug resistant Pseudomonas aeruginosa was detected. Risk factors of blood-borne infection were detected in 2 donors in accidental death group, with detection ratio lower than that in non-accidental death group (7 cases), but the difference was not statistically significant ( χ2=0.562, P>0.05). (4) A total of 8 donors′ abnormal skin tissue were selected, including 4 cases of intradermal pigmented nevus, 1 case of scar, 1 case of pseudoepithelioma hyperplasia, 1 case of epidermal verrucous hyperplasia, and 1 case of large amount of pigment granules in dermis. Conclusions:Non-accidental death caused by diseases is the main cause of death of skin tissue donors, and the risk of donor-derived infection of non-accidentally dead donors is slightly higher than that of accidentally dead donors. Before the allogeneic skin is obtained and transplanted, the cause of death of the donor should be carefully investigated, and the health status should be evaluated, so as to avoid the occurrence of donor-derived infection.

Objective To explore the regulation of Chaihuang Qingyi Huoxue Granule on intestinal microecological changes in rats with severe acute pancreatitis (SAP) and the potential mechanism for its treatment of SAP. Methods Forty-eight rats were randomly divided into sham operation group (SHAM),SAP model group (SAP),and Chaihuang Qingyi Huoxue Granule (CH)group,with 16 rats in each group. Each group was further divided into 12 h and 24 h subgroups. The SAP model was induced by retrograde injection of 5％ sodium taurocholate into the pancreaticobiliary duct through duodenal wall. The SHAM and SAP groups received normal saline by gavage,while the CH group received 1.2 g·kg-1 Chaihuang Qingyi Huoxue Granule solution by gavage every six hours. At 12 h and 24 h after operation,eight rats from each group were sacrificed to collect abdominal aortic blood,pancreatic and ileal tissues for analysis. Ascites,pancreatic and ileal tissues were observed. Serum amylase(AMY) and lipase (LPS) levels were measured biochemically. Pathological changes in pancreatic and ileal tissues were investigated by HE staining. Claudin-1 protein expression in ileal tissue was detected by Western Blot. Changes in the intestinal flora of ileocecal contents were analyzed by 16S rDNA high-throughput sequencing. Results Compared to the SHAM group at the same time points,the SAP group exhibited extensive pancreatic edema and necrosis. Serum AMY and LPS levels,pancreatic and ileal histopathological scores increased,and Claudin-1 protein expression in ileal tissue markedly decreased (all P<0.05). The differences in abundance of microbial community increased,while the evenness of community composition reduced. The microbial richness showed no significant change (P>0.05),but the microbial diversity decreased(P<0.05). Proteobacteria were dominant intestinal bacteria. Relative abundances of Oscillospira,Ruminococcus,Bifidobacterium,and Bacteroides S24-7 decreased,whereas relative abundances of Shigella and Allobaculum increased. The differences in abundance of microbial community reduced,and the evenness of community composition increased. The microbial richness showed no significant change(P>0.05),but the microbial diversity increased (P<0.05). Firmicutes and Bacteroidetes were the dominant intestinal bacteria. Relative abundances of Oscillospira,Ruminococcus,Bifidobacterium,and Bacteroides S24-7 increased,whereas relative abundances of Shigella and Allobaculum decreased. After the intervention of CH,pathological damage in ileal tissue was improved. The expression of Claudin-1 protein in the intestinal mucosal barrier increased compared to the model group(P<0.05). The differences in abundance of microbial community reduced,and the evenness of community composition increased. CH group showed an increase in some beneficial bacteria and decrease in pathogenic bacteria compared to model group. Conclusion Chaihuang Qingyi Huoxue Granule may reduce pancreas injury in rats with SAP,which may be involved in modulating the intestinal microecology and improving intestinal mucosal barrier function.

OBJECTIVETo investigate the mechanism of drug resistance of carbapenems-resistant Acinetobacter baumannii (CRAB) in burn patients and the antimicrobial activity of a combination of drugs against this bacteria in vitro.

METHODSA total of 135 strains of Acinetobacter baumannii (AB) from wound excretion, sputum, and venous catheter wall of patients hospitalized in our department from January 2011 to July 2013 were collected individually. Drug resistance of 135 strains of AB to 12 antibiotics commonly-used in clinic was detected using K-B paper diffusion method. Among the CRAB strains, double-disk synergy test was used to screen metallo-β-lactamase (MBL)-producing strains, and the drug resistance rates between MBL-producing strains and non-MBL-producing strains were compared. Minimal inhibitory concentration (MIC), 50% MIC (MIC50), and 90% MIC (MIC90) of cefoperazone/sulbactam, imipenem, cefepime, ampicillin/sulbactam, and amikacin used alone against MBL-producing CRAB were determined by broth microdilution method. MIC, MIC50, and MIC90 of amikacin respectively combined with imipenem, cefoperazone/sulbactam, cefepime, or ampicillin/sulbactam against MBL-producing CRAB were determined by checkerboard method with diluted agar. Fractional inhibitory concentration (FIC) index was calculated to determine the antibacterial effect of each combination of two antibiotics. Synergy with FIC lower than or equal to 0.5, or additivity with FIC higher than 0.5 and lower than or equal to 1.0 was regarded as effective, and indifference with FIC higher than 1.0 and lower than or equal to 2.0 or antagonism with FIC higher than 2.0 was regarded as ineffective. The effective rate was calculated. Data were processed with Chi-square test.

RESULTSThe resistant rates of the 135 strains of AB to imipenem, meropenem, and ceftazidime were high, and those of piperacillin/tazobactam and ampicillin/sulbactam were low. A total of 120 strains of CRAB was screened, accounting for 88.89%, among which the MBL-producing strains accounted for 78.33% (94/120). The resistant rates of MBL-producing strains to piperacillin/tazobactam, imipenem, meropenem, piperacillin, and cefepime were respectively 59.5%, 87.2%, 93.5%, 87.0%, 86.0%, and they were significantly higher than those of non-MBL-producing strains (respectively 43.0%, 81.3%, 87.5%, 78.4%, 64.0%, with χ(2) values from 4.571 to 8.260, P < 0.05 or P < 0.01). Among the inhibition concentrations of each of the 5 antibiotics used alone against MBL-producing strains, MIC, MIC50, and MIC90 of ampicillin/sulbactam were the lowest, respectively 4.00, 16, 64 µg/mL, while those of cefepime were high, respectively 32.00, 128, 512 µg/mL. MIC, MIC50, and MIC90 of amikacin combined with each of the other 4 antibiotics were decreased from 50.00% to 98.44% as compared with that of single administration of each antibiotic. Among the 94 strains of MBL-producing CRAB, the synergic, additive, indifferent, and antagonistic effects were respectively observed in 40, 33, 6, and 15 strains applied with combination of amikacin and ampicillin/sulbactam; 42, 30, 5, 17 strains applied with combination of amikacin and cefoperazone/sulbactam; 38, 15, 19, 22 strains applied with combination of amikacin and cefepime; 34, 2, 37, 21 strains applied with combination of amikacin and imipenem, among which the antibacterial effective rates decreased successively, respectively 77.7%, 76.6%, 56.4%, and 38.3%. The former two rates were respectively significantly higher than the latter two rates (with χ(2) values from 8.618 to 29.889, P values below 0.01).

CONCLUSIONSProduction of MBL is the main mechanism of resistance of the CRAB isolated from burn patients hospitalized in our department against carbapenems in about 3 years. The antibacterial effects of amikacin combined with each of the former-mentioned 4 agents are better than those of each of the five antibiotics used singly, and the effects are particularly obvious when combining amikacin with compound agent containing enzyme inhibitors.

Acinetobacter Infections ; drug therapy ; microbiology ; Acinetobacter baumannii ; drug effects ; isolation & purification ; Ampicillin ; pharmacology ; Anti-Bacterial Agents ; pharmacology ; Carbapenems ; pharmacology ; Cephalosporins ; pharmacology ; Drug Resistance ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; Penicillanic Acid ; analogs & derivatives ; pharmacology ; Pharmaceutical Preparations ; Piperacillin ; pharmacology ; Sulbactam ; pharmacology ; Thienamycins ; pharmacology ; beta-Lactamase Inhibitors ; pharmacology

OBJECTIVETo observe the changes in the expressions of microRNA-126 in myocardial tissue and cardiac troponin I (cTnI) in serum of rats in the early stage of severe burn injury with analysis of their relationship, and to validate the relationship between microRNA-126 and myocardial damage in cellular level.

METHODS(1) Forty-eight SD rats were divided into sham injury group (n=8, without fluid therapy after sham injury) and burn injury group (n=40, inflicted with 30% TBSA full-thickness scald on the back, hereinafter referred to as burn, and received intraperitoneally injection of lactic acid Ringer's solution) according to the random number table. Blood was collected from abdominal aorta of rats in sham injury group at post injury hour (PIH) 1, and then these 8 rats were sacrificed for obtaining left ventricular tissue. Blood was respectively collected from abdominal aorta of 8 rats in burn injury group at PIH 3, 6, 12, 24, and 48, and then they were sacrificed and the left ventricular tissue was obtained at each time point. The expression of microRNA-126 in myocardial tissue was assessed by real-time fluorescent quantitative RT-PCR. Serum level of cTnI was assessed by ELISA. (2) Rat myocardial cell line H9C2 was divided into normal control group (NC, routinely cultured), stimulation group (S), negative transfection+stimulation group (NT+S), and transfection+stimulation group (T+S) according to the random number table. Cells in S group were treated with hypoxia for 24 h after being cultured with DMEM containing 10% burn serum obtained from rats in burn injury group at PIH 6 in experiment (1). Cells in NT+S group and T+S group were respectively transfected with the negative control of microRNA mimics and microRNA-126 mimics for 24 h, and then were given the same treatment as that of S group. The expression of microRNA-126 in myocardial cells was determined by real-time fluorescent quantitative RT-PCR (with the sample number of 3). Cell counting kit 8 was used to examine the vitality of myocardial cell (with the sample number of 4, denoted as absorbance value). Apoptotic rate of myocardial cells was determined by flow cytometer (with the sample number of 3). Data were processed with one-way analysis of variance and LSD-t test. The relationship between microRNA-126 expression in myocardial tissue and serum level of cTnI of rats was assessed by linear correlation analysis.

RESULTS(1) Compared with that of sham injury group at PIH 1, the expression levels of microRNA-126 in myocardial tissue of rats in burn injury group at PIH 3, 6, 12, 24, and 48 were significantly decreased (with t values from 5.68 to 9.79, P values below 0.01), reaching its nadir at PIH 24 (0.40 ± 0.08). Compared with that of sham injury group at PIH 1, the serum levels of cTnI of rats in burn injury group at PIH 3, 6, 12, 24, and 48 were significantly increased (with t values from 6.68 to 12.79, P values below 0.01), peaking at PIH 12 [(1 035 ± 177) pg/mL]. A significant negative correlation between the expression level of microRNA-126 in myocardial tissue and serum level of cTnI was observed in rats of burn injury group at each time point (r=-0.797, P<0.001). (2) Compared with those of NC group, the microRNA-126 expression levels in myocardial cells of S group and T+S group were respectively decreased and increased (with t values respectively 4.57 and 5.73, P<0.05 or P<0.01), the cell vitality levels were obviously decreased (with t values respectively 14.88 and 6.48, P values below 0.01), and the apoptotic rates were significantly increased (with t values respectively 13.82 and 6.96, P values below 0.01). Compared with that in NT+S group, the microRNA-126 expression level in myocardial cells of T+S group was significantly increased (t=6.77, P<0.01), the cell vitality level was obviously increased (t=8.23, P<0.001), and the apoptotic rate was significantly decreased (t=6.14, P<0.001).

CONCLUSIONSExpression level of microRNA-126 in myocardial tissue of rat was decreased in the early stage of severe burn injury. It may participate in regulating myocardial damage and play a protective role.

Animals ; Burns ; metabolism ; pathology ; Cell Line ; Enzyme-Linked Immunosorbent Assay ; Hypoxia ; MicroRNAs ; genetics ; metabolism ; Myocardium ; metabolism ; pathology ; Myocytes, Cardiac ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Reverse Transcriptase Polymerase Chain Reaction ; Serum ; Soft Tissue Injuries ; Transfection ; Troponin I ; metabolism

OBJECTIVETo observe the change in phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signal pathway in monocytes as induced by serum of rats with electrical burn, and to explore the effects of PI3K/Akt pathway on monocyte-endothelial cell adhesion.

METHODSSixty-four SD rats of clean grade were inflicted with electrical burn for the collection of serum of rats with electrical burn; another group of twenty-four SD rats were used to obtain normal serum without treatment. (1) Human monocyte line THP-1 was routinely cultured. The THP-1 cells in logarithmic phase were divided into normal serum group (resuspended in RPMI 1640 medium with 20% normal rat serum) and burn serum group (resuspended with RPMI 1640 medium with 20% serum of rats with electrical burn) according to the random number table, with 6 wells in each group. Morphology of THP-1 cells in normal serum group was observed at post culture hour (PCH) 24, and that in burn serum group at PCH 3, 6, 24. The contents of TNF-α in culture supernatant were determined by double-antibody sandwich ELISA at the corresponding time point in each group. The state of Akt activation was determined by Western blotting at PCH 3, 6, 24. (2) Another portion of THP-1 cells were divided into 4 groups according to the random number table, with 6 wells in each group. Cells in normal serum group and burn serum group were given with the same culture condition as above; cells in normal serum+inhibitor group and burn serum+inhibitor group were cultured with the same culture conditions as in the former two groups correspondingly with addition of 100 nmol/L wortmannin in the nutrient solution. At PCH 3 and 6, THP-1 cells were added into the well with a monolayer of endothelial cell line EA.hy926 to observe the monocyte-endothelial cell adhesion. Data were processed with one-way analysis of variance and LSD- t test.

RESULTS(1) In normal serum group, THP-1 cells showed growth in suspension, with uniform shape at PCH 24. In burn serum group, the cell shape became irregular though the membrane was complete at PCH 3; cellular size became irregular and cell membrane and cytoplasm were swollen at PCH 6; cell membrane was disrupted with death of cells at PCH 24. The contents of TNF-α in culture supernatant in normal serum group at PCH 24 and in burn serum group at PCH 3, 6, 24 were respectively (38.5 ± 1.4), (75.1 ± 1.5), (91.5 ± 1.8), (117.0 ± 1.4) pg/mL (F = 1 415.306, P < 0.01). The contents of TNF-α in culture supernatant in burn serum group at PCH 3, 6, 24 were all significantly higher than the content of TNF-α in normal serum group at PCH 24 (with t values respectively 29.614, 42.852, 63.485, P values below 0.01). The ratio values of phosphorylated Akt to Akt in burn serum group at PCH 3, 6, 24 were respectively 2.66, 3.69, 1.17 times of those in normal serum group at the corresponding time point. (2) In normal serum group, normal serum+inhibitor group, burn serum group, and burn serum+inhibitor group at PCH 3 and 6, the numbers of THP-1 cells adherent to endothelial cells were respectively (231 ± 45), (280 ± 47), (703 ± 169), (335 ± 85) per 100-time field; (219 ± 49), (235 ± 21), (562 ± 123), (226 ± 29) per 100-time field (with F values respectively 25.630 and 18.975, P values below 0.01). The number of THP-1 cells adhered to EA.hy926 cells was significantly more in burn serum group than in normal serum group at PCH 3 and 6 (with t values respectively 6.189 and 6.601, P values below 0.01). The number of THP-1 cells adherent to EA.hy926 cells was significantly fewer in burn serum+inhibitor group than in burn serum group at PCH 3 and 6 (with t values respectively 6.821 and 6.465, P values below 0.01).

CONCLUSIONSThe serum of rats suffering from electrical burn can induce the monocytes to secrete TNF-α, thus enhancing monocyte-endothelial cell adhesion, but it can be inhibited by blocking PI3K/Akt signal pathway.

Animals ; Burns, Electric ; blood ; Cell Line ; Humans ; Monocytes ; Phosphatidylinositol 3-Kinases ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Serum ; Signal Transduction ; Tissue Adhesions ; metabolism ; pathology ; Tumor Necrosis Factor-alpha ; metabolism