Objective:To explore the effect of oxidative stress on cognitive function following chest blast injury in mice.Methods:Sixty male C57BL/6 mice were divided into control group ( n=15) and chest blast group ( n=45) according to a random number table. The chest blast group was subgrouped at 1, 3, 7 days after injury for subsequent experiments. A self-developed blast injury device was used to prepare the mouse model of chest blast injury. Toklu score was used to evaluate the behavior changes in mice. Morris water maze test was used to evaluate the changes in spatial memory. HE staining was used to observe the pathological changes in the frontal cortex and hippocampus. Tissue reactive oxygen species (ROS) assay kit was used to detect ROS expression in the frontal cortex and hippocampus. Western blotting was used to assess changes of malondialdehyde (MDA) and cyclooxygenase-2 (COX2) in the frontal cortex and hippocampus. Results:The Toklu score of the chest blast group at 1 day after injury was (6.7±2.1)points, significantly higher than that of the control group [(2.0±0.0)points], as well as those of the chest blast group at 3 and 7 days after injury [(2.7±1.2)points and (2.0±0.0)points] (all P<0.01). There was no significant difference in the Toklu score between the control group and the chest blast group at 3 and 7 days after injury (all P>0.05). The Morris water maze test showed that the latency periods at 1 and 3 days after injury were 60.1(60.1, 60.1)seconds and 60.1(56.3, 60.1)seconds, significantly longer than that of the control group [10.1(3.9, 18.3)seconds] (all P<0.01). The latency period of the chest blast group at 7 days after injury was 60.1(30.5, 60.1)seconds, with no difference from the control group ( P>0.05). No significant differences were found in the latency periods of the chest blast group at 1, 3 and 7 days after injury (all P>0.05). In the control group, the pyramidal cells in the frontal cortex and hippocampus were regular in shape, with intensely-stained and clearly visible nuclei as well as uniform cytoplasm. In the chest blast group, diflerent degree of necrosis of pyramidal cells in the frontal cortex and strong cytoplasmic eosinophilia in the hippocampus were observed at different time points after injury. The levels of ROS in the frontal cortex of the chest blast group were (10.43±0.36)RFU/mg and (2.91±0.35)RFU/mg at 3 and 7 days after injury, which were significantly higher than that of the control group [(0.70±0.01)RFU/mg] ( P<0.05 or 0.01). The level of ROS in the frontal cortex of the chest blast group at 3 days after injury was significantly higher than that at 1 day [(2.13±0.65)RFU/mg] and that at 7 days after injury (all P<0.01). There were no statistical differences in the levels of ROS in the frontal cortex of the chest blast group at 1 and 7 days after injury ( P>0.05). The levels of ROS in the hippocampus of the chest blast group were (5.39±0.79)RFU/mg and (5.65±1.17)RFU/mg at 3 and 7 days after injury, which were significantly higher than those of the control group and of the chest blast group at 1 day after injury [ (0.73±0.06)RFU/mg and (2.33±0.02)RFU/mg] (all P<0.01). No significant differences were found between the levels of ROS in the hippocampus of the chest blast group at 3 and 7 days after injury and between the ROS levels of the control group and of the chest blast group at 1 day after injury (all P>0.05). The levels of ROS in the frontal cortex and hippocampus showed significant differences between the chest blast group at 3 and 7 days after injury (all P<0.01) but no significant differences between the control group and the chest blast group at 1 day after injury (all P>0.05). Western blotting showed that the levels of MDA in the frontal cortex of the chest blast group were 0.73±0.04, 0.83±0.04 and 0.99±0.06 at 1, 3 and 7 days after injury, which were significantly higher than that of the control group (0.56±0.04) ( P<0.05 or 0.01). The level of MDA in the frontal cortex of the chest blast group was significantly higher at 7 days after injury compared with that at 1 and 3 days after injury ( P<0.05 or 0.01), but there was no statistical difference between 1 day and 3 days after injury ( P>0.05). The levels of COX2 in the frontal cortex of the chest blast group were 2.93±0.02, 4.82±0.15 and 4.76±0.06 at 1, 3 and 7 days after injury, which were significantly higher than that of the control group (1.93±0.06) (all P<0.01). There were statistical differences in the levels of COX2 in the frontal cortex of the chest blast group at 3 and 7 days after injury compared with that at 1 day after injury (all P<0.01), but no statistical significance was found between 3 and 7 days after injury ( P>0.05). The levels of MDA in the hippocampus of the chest blast group were 0.92±0.11, 0.83±0.03 and 0.68±0.03 at 1, 3 and 7 days after injury, which were significantly higher than that of the control group (0.49±0.03) (all P<0.01). There was a significant difference in the level of MDA in the hippocampus of the chest blast group at 7 days after injury compared with those at 1 and 3 days after injury ( P<0.05 or 0.01), but the difference was not statistically significant among other groups (all P>0.05). The levels of COX2 in the hippocampus of the chest blast group were 0.88±0.06, 0.87±0.06 and 0.80±0.06 at 1, 3 and 7 days after injury, which were significantly higher than that of the control group (0.37±0.04) (all P<0.01). There were significant differences in the levels of COX2 of the chest blast group among 1, 3 and 7 days after injury (all P>0.05). Statistically significant differences were found between the levels of MDA in the frontal cortex and hippocampus of the chest blast group at 1 and 7 days after injury (all P<0.01), but no statistical significant difference between the control group and the chest blast group at 1 day after injury ( P>0.05). The levels of COX2 in the frontal cortex and hippocampus were significantly different among all groups (all P<0.01). Conclusions:In the short term after chest blast injury, there will be cognitive dysfunction in mice. Oxidative stress is one of the important contributing factors, and the cognitive damage in the frontal cortex is more serious than that in the hippocampus.

Objective:To prepare the chitin/hyaluronic acid/collagen hydrogel loaded with mouse adipose-derived stem cells and to explore its effects on wound healing of full-thickness skin defects in rats.Methods:The research was an experimental research. Chitin nanofibers were prepared by acid hydrolysis and alkaline extraction method, and then mixed with hyaluronic acid and collagen to prepare chitin/hyaluronic acid/collagen hydrogels (hereinafter referred to as hydrogels). Besides, the hydrogels loaded with mouse adipose-derived stem cells were prepared. Thirty male 12-week-old guinea pigs were divided into negative control group, positive control group, and hydrogel group according to the random number table, with 10 guinea pigs in each group. Ethanol, 4-aminobenzoic acid ethyl ester, or the aforementioned prepared hydrogels without cells were topically applied on both sides of back of guinea pigs respectively for induced contact and stimulated contact, and skin edema and erythema formation were observed at 24 and 48 h after stimulated contact. Adipose-derived stem cells from mice were divided into normal control group cultured routinely and hydrogel group cultured with the aforementioned prepared hydrogels without cells. After 3 d of culture, protein expressions of platelet-derived growth factor-D (PDGF-D), insulin-like growth factor-Ⅰ (IGF-Ⅰ), and transforming growth factor β 1 (TGF-β 1) were detected by Western blotting ( n=3). Eight male 8-week-old Sprague-Dawley rats were taken and a circular full-thickness skin defect wound was created on each side of the back. The wounds were divided into blank control group without any treatment and hydrogel group with the aforementioned prepared hydrogels loaded with adipose-derived stem cells applied. Wound healing was observed at 0 (immediately), 2, 4, 8, and 10 d after injury, and the wound healing rate was calculated at 2, 4, 8, and 10 d after injury. Wound tissue samples at 10 d after injury were collected, the new tissue formation was observed by hematoxylin-eosin staining; the concentrations of interleukin-1α (IL-1α), IL-6, IL-4, and IL-10 were detected by enzyme-linked immunosorbent assay method; the expressions of CD16 and CD206 positive cells were observed by immunohistochemical staining and the percentages of positive cells were calculated. The sample numbers in animal experiment were all 8. Results:At 24 h after stimulated contact, no skin edema was observed in the three groups of guinea pigs, and only mild skin erythema was observed in 7 guinea pigs in positive control group. At 48 h after stimulated contact, skin erythema was observed in 8 guinea pigs and skin edema was observed in 4 guinea pigs in positive control group, while no obvious skin erythema or edema was observed in guinea pigs in the other two groups. After 3 d of culture, the protein expression levels of PDGF-D, IGF-I, and TGF-β 1 in adipose-derived stem cells in hydrogel group were significantly higher than those in normal control group (with t values of 12.91, 11.83, and 7.92, respectively, P<0.05). From 0 to 10 d after injury, the wound areas in both groups gradually decreased, and the wounds in hydrogel group were almost completely healed at 10 d after injury. At 4, 8, and 10 d after injury, the wound healing rates in hydrogel group were (38±4)%, (54±5)%, and (69±6)%, respectively, which were significantly higher than (21±6)%, (29±7)%, and (31±7)% in blank control group (with t values of 3.82, 3.97, and 4.05, respectively, Pvalues all <0.05). At 10 d after injury, compared with those in blank control group, the epidermis in wound in hydrogel group was more intact, and there were increases in hair follicles, blood vessels, and other skin appendages. At 10 d after injury, the concentrations of IL-1α and IL-6 in wound tissue in hydrogel group were significantly lower than those in blank control group (with tvalues of 8.21 and 7.99, respectively, P<0.05), while the concentrations of IL-4 and IL-10 were significantly higher than those in blank control group (with tvalues of 6.57 and 9.03, respectively, P<0.05). The percentage of CD16 positive cells in wound tissue in hydrogel group was significantly lower than that in blank control group ( t=8.02, P<0.05), while the percentage of CD206 positive cells was significantly higher than that in blank control group ( t=7.21, P<0.05). Conclusions:The hydrogel loaded with mouse adipose-derived stem cells is non-allergenic, can promote the secretion of growth factors in adipose-derived stem cells, promote the polarization of macrophages to M2 phenotype in wound tissue in rats with full-thickness skin defects, and alleviate inflammatory reaction, thereby promoting wound healing.

Objective To study the predictive value of serum lactate/albumin ratio(LAR)and monocyte/high-density lipoprotein cho-lesterol ratio(MHR)for the prognosis of patients with acute upper gastrointestinal bleeding.Methods Clinical data were collected from 440 patients with acute upper gastrointestinal bleeding treated at the Emergency Department of General Hospital Northern Theater Com-mand from January 2019 to October 2021.According to whether the main clinical outcome event of acute upper gastrointestinal bleeding occurred(death for any reason,recurrence of gastrointestinal bleeding,requirement for emergency surgery,interventional surgery),patients were divided into the main clinical outcome event group(group A,n=91)and the no-main clinical outcome event group(group B,n=349).A logistic regression analysis analyzed the factors influencing the main clinical outcome events.Receiver operating character-istic(ROC)curves,integrated discrimination improvement(IDI),net reclassification index(NRI),and calibration curves were used to ana-lyze the predictive efficacy of an early dynamic elevated LAR alone,MHR alone,and a combination thereof.Results The logistic regres-sion analysis showed that elevated LAR and MHR,increased age,and reduced hemoglobin and hematocrit levels were independent risk factors for the occurrence of the main clinical outcomes(all P<0.05).A correlation analysis showed that hemoglobin level was negatively correlated with MHR and LAR(r=-0.165 and-0.247,all P<0.01).Alanine aminotransferase(ALT)and prothrombin time(PT)were positively correlated with LAR(r=0.165 and 0.178,all P<0.01).PT was positively correlated with MHR(r=0.142,P<0.01).The ROC curve analysis results showed that the area under the curve of LAR alone,MHR alone,and the combination thereof was 0.665(95%CI:0.598-0.731),0.863(95%CI:0.821-0.905),and 0.886(95%CI:0.845-0.927),while the cut-off values of LAR and MHR were 0.332 and 0.715,respectively.The IDI,NRI,and calibration curve results showed that the predictive value of LAR plus MHR for the occurrence of the main clinical outcome event was better than that of either alone.The sensitivity and specificity of LAR plus MHR were 84.6%and 88.5%,respectively.Conclusion Early dynamic elevation of LAR and MHR has high predictive value for the main clinical outcome events in patients with acute upper gastrointestinal bleeding,and the predictive value of LAR plus MHR is better than that of either alone.