| Objective: In our experiment through the establishment of pig intestinal firearm wound model, to observe the changes of cardiac structure and function, and dynamic changes of endotoxin in plasma and LDH,CK,CK-MB in blood serum,as well as the expression of cadiocyte iNOS,NF–κB and cardiomyocyte apoptosis after injury, to investigate the relationships between cytokines,such as iNOS,and cardiac injury, and their roles in the cardiac injury after intestinal firearm wound, so as to provide academic and experimental evidence of the prevention and treatment of subsequent cardiac injury after intestinal firearm wound.Methods: Forty two Chang-Bai piglets were randomized into 7 groups: control group and wounded 1 hour group, 2 hour group, 4 hour group, 8 hour group, 12 hour group, 24 hour group. all of the piglets in experimental group were shot (at the location of hairless areas at inferior border of the plica at the right side of the abdominal wall, 2 cm behind umbilicus) by military 54 gun after anesthesia at normal environment (Temperature 22℃-24℃, Relative Humidity 50%-60%) to establish the pig intestinal firearm wound model. The piglets in control group were not shot, but the remaining steps were the same. The blood and liver were collected at corresponding time in experimental group and after returning to laboratory in control group. The changes of cardiac tissue were observed under light microscope in all groups, and the levels of serum LDH,CK and CK-MB were also detected at the same time; The Plasma endotoxin levels were measured by chromogenic limulus amebocyte lysate test; The cardiac myocyte apoptosis index were determined by Tunnel; cardiac iNOS,NF–κB expressions were measured with immunohistochemical staining and image analysis.Results: (1) The appearance of heart was normal. Under light microscope, cadiocytes were stained consistenty and arranged neatly, the endothelium of arterial and venous was integrate in the group of control,1h and 2h, the myocardial capillary was hyperemia in the group of 1h and 2h. the changes of Myocardial cell edema,band gap widened and eosinophilic variant was gradually aggravated from 4h group to 24h group. (2) Serum LDH,CK and CK-MB levels of the experimental group were significantly higher than those of control group (P<0.01). Overall analysis, the increased rate of each myocardial Enzymes was rapid in group of 1h,2h ; there was a gradually upward trend in overall in group of 4h,8h,12h in spite of the rate was slow; the increased rate of each myocardial Enzyme was rapid in group of 24h again. (3) Plasma endotoxin levels of the experimental group were significantly higher than that of control group (P<0.05), 8 h after injury in the peak, 12 h after injury remained at peak levels. (4) Myocardial NF-κB expressions of the experimental group were significantly higher than those in control group (P<0.01). There was Rapid increase of the NF-κB expression in myocardial tissue within 2h after injury. The expression of NF-κB in myocardial tissue rose in group of 8h,12h,but the IOD of every group was higher than the before(P<0.05). It rapidly increased again in the group of 24h (P<0.01) and reached a peak value. (5) The expression of iNOS in myocardial tissue in each group after injury were significantly higher than that in control group (P<0.01). There was rapid increase of the iNOS expression in myocardial tissue within 2h after injury. The expression of iNOS in myocardial tissue rose in group of 4h,8h,12h,but the IOD of every group was higher than before(P<0.05). It rapidly increased again in the group of 24h (P<0.01) and reached a peak value. (6) The percentage of myocardial apoptotic cells was sharply increased within 2h.The number of apoptotic cells Still showed an increase trend from 2h to 8h, but increased less. There was no statistical significance between the group of 4h and 8h. The increased percentage of myocardial apoptotic cells rapidly upstroke again from 12h to 24h.(7) Correlation analysis showed that the expression of iNOS in myocardial tissue were positively correlated with LDH,CK,CK-MB of serum, the expression of NF-κB, the percentage of myocardial apoptotic cells and endotoxin after intestinal firearm wound (r=0.986,0.994,0.984,0.980,0.935,0.778, respectively, all P<0.01); the expression of NF-κB in myocardial tissue were positively correlated with LDH,CK,CK-MB of serum, the percentage of myocardial apoptotic cells and endotoxin, (r=0.968,0.971,0.957,0.941,0.790,all P<0.01).Conclusion: (1) Intestinal firearm wound induces heart functional and morphological injury, which aggravates with prolongation of wound. (2) the NF–κB,iNOS in myocardial cell can be induced by intestinal firearm wound and mediates the heart injury. Complex trauma and complicated endotoxin-cytokine network play important roles in the occurrence and the development of subsequent heart injury after abdominal firearm injury. |
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