The Study On The Changes Of Myocardial Function And Mitochondrial Biology In Sepsis Rats

Objective: To investigate the evaluation of cardiac function in rats with sepsis induced by cecal ligation and perforation(CLP)by high resolution ultrasound.And to investigate the biogenesis of myocardial mitochondria in sepsis.Methods: According to the method of random number table,48 adult male Sprague-Dawley(SD)rats were randomly divided into normal control group and sepsis 6,12,24,30,48 hours groups,with 8 rats in each group.The sepsis model was produced by CLP,and the rats in the normal control group were only anesthetized and resuscitated.The general situation after modeling in each group was observed,and the left ventricular function was assessed by high-resolution echocardiography at all the time points.The abdominal aorta blood of rats was collected,and the serum levels of tumor necrosis factor-?(TNF-?),interleukin-1?(IL-1?)and MB isoenzyme of creatine kinase(CK-MB)were determined by enzyme-linked immunosorbent assay(ELISA).The myocardial tissue was harvested,and the pathological changes in myocardial tissue were observed by hematoxylin-eosin(HE)staining.The structural changes of myocardial mitochondria in rats were observed by transmission electron microscopy.Myocardial tissue was taken to detect tissue ATP level;myocardial mitochondria were extracted,detection of PGC-1?,NRF-1 and TFAM expression by Western blot.Results: After the CLP model,the rats in the sepsis group showed symptoms such as mental depression,curling of the hair,reduced diet and activity,which was consistent with the general performance of the rat model of sepsis,and the symptoms gradually increased with time Serum inflammatory factors TNF-?,IL-1? levels were higher than the normal control group(P<0.05).The heart rate(HR)of rats in each group of sepsis measured by high-resolution ultrasound gradually increased with the extension of modeling time.The 12,24,and 30-hour groups were significantly higher than the normal control group(P<0.05);The stroke volume(SV)and cardiac output(CO)of the rats all showed a decreasing trend with the extension of the modeling time,while the left ventricular ejection fraction(LVEF)and the left ventricular short axis shortening rate(FS)showed the first increase After the reduction,the SV and LVEF of the 48-hour sepsis group were significantly lower than the normal control group(P<0.05);Compared with the normal control group,the left ventricular mass(LV)of rats in each group of sepsis increased to varying degrees,and the thickness of the anterior and posterior walls of the left ventricular end diastole and end systole increased.Compared with the normal control group,the left The thickness of the posterior wall of the ventricle increased significantly at the end of diastole and systole in 12 hours(P<0.05);The thickness of the anterior wall of the left ventricle also increased significantly at the end of diastole in 48 hours(P<0.05).With the prolonged modeling time,the level of myocardial enzyme index CK-MB in sepsis rats increased first and then decreased.The 48 h group was still higher than the normal control group(P<0.05).HE staining results showed that the myocardial stripes of the normal control group were clear and structurally complete,and the myocardial cells were normal in shape and arranged neatly;the myocardial cells of the sepsis group showed different degrees of swelling,rupture,necrosis,inflammatory cell infiltration,heart Muscle fibers break,and the degree gradually increases with the extension of the molding time.Transmission electron microscopy showed that the mitochondria of septic rats were swollen and destroyed,and the density of mitochondrial matrix decreased.Compared with the normal control group,the myocardial mitochondrial ATP content of rats in each group of sepsis decreased,and the results were statistically significant(P<0.05);The protein expression levels of PGC-1?,NRF-1 and TFAM in myocardial mitochondria of rats in each group of sepsis were enhanced(P<0.05).Conclusion: High-resolution ultrasound can comprehensively evaluate the cardiac function performance of the model rats with sepsis induced by CLP,and the results of the evaluation indexes were consistent with the histopathological manifestations of myocardial enzyme expression.In sepsis rats,the myocardial mitochondrial biogenesis is enhanced.