The Function And Mechanism Of Calpain In Myocardial Damage Induced By Burn-blast Combined Injury

Objective:Burn-blast combined injury is one of the most common type of injury. when the pathological changes in the heart and lung damage, abnormal immune response in serum transaminase inhibition of endothelial cell injury are more single burn or a single blast injury is more serious and myocardial injury far-reaching,Recent studies have shown that calpain after activation can lead to cardiac myocyte apoptosis, causing myocardial systolic function decline,in order to provide experimental evidence for clinical treatment, this study by severe burn-blast combined injury animal models and in vitro experiments to explore:(1) Study on the changes of myocardial injury and calpain in rats with burn-blast combined injury (2) To investigate the pathogenesis of calpain in myocardial injury induced by burn-blast combined injury and find a new method for clinical treatment.;(3) therapeutic effect and mechanism of FDP in rat myocardial damage induced by burn-blast combined injury.Method:The experiment is divided into three parts, first part is Select male SD rats,divided into:control group;burn group;blast injury group; burn-blast combined injury group, second part:Use a random number table to divide male SD rats into burn-blast combined injury group, MDL28170 inhibitor group and Ac-DEVD-Cho inhibitor group,(Cell Experiment)H9C2 in vitro,divided into:control group;burn-blast combined injury group,MDL2817group,Ac-DEVD-Cho inhibitor group.synthesized siRNA into cells in vitro H9C2(1)control group(2)experimental group(BB)(3) scrambl+ BB group(4)siRNA+BB group;third part:Randomly, male SD rats,divided into:control group, the burn-blast combined injury group and FDP group.At 6h, 24h, 48h, 72h observation points after injury,and myocardial blood collected abdominal aorta specimens.By three-dimensional echocardiography left ventricular ejection fraction, left ventricular fractional shortening index; myocardial tissue HE staining; TEM myocardial tissue over micro-structural changes;Tunel staining of myocardial tissue apoptosis;real-time quantitative PCR assay calpain and calpastatin expression levels; fluorescence quantitative detection of calpain activity. Western blot Western blot analysis myocardium calpain,calpastatin,activated Bid, cytochrome c, glucose-regulated protein 78, CHOP,B-cell lymphoma 2 gene, Bcl-2 associated X protein expression. Electron probe X-ray microanalysis was used to detect myocardial cytosolic Ca2+content.Results:Part ? :Ejection fraction decline,myocardial enzymes or troponin, myocardial apoptosis index were significantly increased;GRP78,CHOP, Bax,Cytc,Bid protein expression,caspase-3,12 activity,calapin protein and mRNA levels was significantly increased,Bcl-2 protein expression and calpastatin is reversed, myocardial cytoplasmic Ca2+ was significantly different.Part II:burn-blast combined injury rats decreased heart function, CTnI,CK-MB,apoptosis index,Grp78,CHOP,Bax,Cytc,Bid and caspase-3,12 protein expression, calapin protein activity was significantly increased than MDL28170 inhibitor group and Ac-DEVD-Cho group. H9C2 cytoplasm Ca2+ concentration calpain consistent trends.after interference calpain gene and protein expression H9C2 cell calpain reduced. RNA interference, the fluorescence intensity is relatively weak. Part?: Heart function slowly decline in FDP group after injury,cTnI,CK-MB trends and burn-blast injury was agreed,GRP78,CHOP,calapin protein activity Cytoplasm Ca2+content had significant differences.Conclusion: (1) burn-blast combined injury increased expression of calpain activity can lead to enhanced cardiac function decreased cardiac function,one of the important reasons (2) after burn-blast combined injury caused by endoplasmic reticulum stress lead to myocardial cells Ca2+ overload activation of calpain promote myocardial apoptosis, primarily through increased mitochondrial outer membrane permeability,resulting in cytochrome c and other pro-apoptotic substance release,leading to apoptosis execution molecule caspase-3 activation caused by apoptosis.(3)calpain inhibitor(MDL28170) and FDP can alleviate the increased expression of calpain activity enhancement caused by decreased cardiac function, for the clinical treatment of severe burn-blast combined function reduces sad provide a theoretical basis.