| Objective:This study was performed cecal ligation and puncture(CLP)on rat to induce sepsis model. By administration of simvastatin drugs, the study compared the difference among enzyme CKMB, myocardium tissue pathological changes and myocardium TNF-α,N0,TLR-4 protein contents in the early/late stages of sepsis, and observed the protection of simvastatin on septic myocardium, which can give some theory ground for sepsis with simvastatin.Methods:30 clean level 4-week-old Wistar male rats whose body weight ranged from 100 to 140 grams were randomly divided into four groups:sham operated group(Sham),septic group(CLP)and simvastatin group(Sim). All rats ate nothing 12 hours before operation. Rats in sham group were turned over cecum after their abdomen opened,which the cecum was located but neither ligated nor puncture; Rats in septic group and simvastatin group were underwent cecal ligation and puncture(CLP); Rats in simvastatin group were administrated by intravenous injection of simvastatin 20mg/kg which dissolved in 10%dimethylsulfoxide(DMSO,lml/kg) subcutaneously after CLP. Rats in other groups were injected with NS 3ml/kg. At 5 and 20 hours after surgery,6 rats were sacrificed in each group, then whose blood and heart tissue samples were collected rapidly. CKMB serum enzyme levels were measured by automatic biochemical analyzer; Heart TNF-a contents were measured by line double antibody sandwich ELISA method, and heart NO contents were analyzed by nitrate reductase assay; pathological lesion of heart tissue was investigated by light microscope. Heart tissue expression of TLR-4 protein was determined by the immunohistochemistry(IHC).Results:1. The rats general observation in each groupThere were no significantly different in the Sham group at all time point; Rats in the CLP group had mental fatigue, lack of exercise, cold, dull coat, erect hair and insensitive, after killed, it was bloody ascites, purulent exudate, odor, cecum swollen, gangrene and adhesions in its abdomen; The changes in the CLP-20h group is more severe than in the CLP-5h group; Compared with the CLP group at all time points, the changes of rats in the Sim group were significantly improved, but somewhat less than those in the Sham group.2. The pathomorphological changes of rats myocardial tissue in each groupThe results showed that the cardiac structure was normal in the Sham group. Diffuse infiltration of inflammatory cells and capillary congestion were observed in the CLP group. Furthermore, extensive necrosis and fibrosis were shown as well in the myocardial cells in the CLP group. The changes in the CLP-20h group is less severe than those in the CLP-5h group; In the Sim group, the degree of the infiltration of inflammatory cells and the myocardial interstitium edema were less severe than those in the CLP group.3. The expression of CKMB in serum of rats in each groupCompared with the CLP group, the expression of CKMB in each group were dramatically decreased, the statistic differences were significant(P<0.01), what's more, the expression of CKMB at CLP-5h was higher than that at CLP-20h(P<0.01). But the expression of CKMB at Sim-5h was lower than that at Sim-20h.4. The expression of TNF-αand NO in myocardial tissue of rats in each groupThe expression of TNF-αand NO in each group were significantly lower than that in the CLP group(P<0.01). Moreover, the expression of TNF-αat CLP-5h was higher than that at CLP-20h(P<0.01), which showed that was an early inflammatory mediator. However, the expression of NO at CLP-20h was higher than that at CLP-5h(P<0.01), which showed that NO was a late inflammatory mediator. The trend of them in the Sim group was similar to that in the CLP group.5. The expression of TLR-4 protein in myocardial tissue of rats in each groupIn the Sham group, expression of TLR-4 protein in most of myocardial tissue was negative; In the CLP group, the expression of TLR-4 protein was detected at 5h and 20h(P<0.01). what's more, the expression of TLR-4 at CLP-5h was higher than that at CLP-20h. In the Sim group, expression was significantly lower than that in the CLP group at all time point(P<0.01).Conclusions:1. The performance of sepsis in this rats' experiment is consistent with the reports from those domestic and foreign documents.2. Myocardial cells is perceptible to inflammatory injured, and might be injured at the beginning of sepsis. Over expression of TNF—α,NO and TLR-4 in myocardial tissue may lead to heart injured.3. Simvastatin could ameliorate heart pathological lesions in sepsis.4. Simvastatin could decrease level of serum CKMB and destruction of myocardial cells.5. Simvastatin could restrain overexpression of TNF—α,NO and TLR-4 protein in myocardial tissue in sepsis.6. By activating the TLR-4 signal transduction pathway in sepsis, Simvastatin might block inflammatory cascade response and prevent sepsis progressing to septic shock or MODS. |
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