内毒素预处理对大鼠心肌缺血－再灌流损伤的保护作用及其分子机制

ENDOTOXIN PRETREATMENT FOR THE PROTECTION OF MYOCARDIUM FROM ISCHEMIA- REPERFUSION INJURY IN RATS AND ITS MOLECULAR MECHANISM

采用大肠杆菌内毒素（５００μｇ／ｋｇ，ｉ．ｐ；）对大鼠进行预处理，从心律失常发生及心肌力学改变观察其对心肌缺血－再灌流损伤的保护作用。发现预处理组室速、室颤发生率及死亡率降低，ＬＶＳＰ及±ｄｐ／ｄｔｍａｘ改善，心肌钙过荷减轻。内毒素预处理的心肌保护机制与心肌中热休克蛋白７０基因表达增加有关。

he effects of pretreatment with E. coli endotoxin(ET)or heat stress on recoverv ofcardiac function after coronary artery(CA)occlusion(5 min)followed by CA release(10min)were evaluated in anesthetized male Wistar rats 24hr after i.p. administration of ET500 μg/kg(or normal saline as control)or hyperthermia(elevated rectal temperature to 42°C for 15 min).The results showed that endotoxin or heat stress pretreatment exhibited sig-nificantly reduced incidence of ventricular tachycardia(VT),ventricular fibrillation(VF),mortality rate(MR)and calcium content in myocardium and mitochondria,and increasedpost-ischemic recovery of LVSP and ± dp/dt max. Northern blot showed an increased levelof myocardial mRNA coding for HSP70 in the animals pretreated with endotoxin or heatstress,The results suggest that endotoxin pretreatment protects myocardium against is-chemia-reperfusion mediated injury,and HSP70 might be responsible for these protective ef-fects.