Proteasome inhibitor improves expressions of CHIP and HSP70 in ischemia reperfusion rats / 第三军医大学学报

ABSTRACT

Objective To explore the influence of proteasome inhibitor, MG-132 (N-benz0y1oxycarbonyl(Z)-Leu-Leuleucina1) on the expressions of carboxyl terminus of the Hsc70-interacting protein (CHIP) and heat shock protein 70 (HSP70) in ischemia reperfusion (I/R) rats and investigate the underlying mechanism of myocardial protection by the inhibitor. Methods Totally 54 adult SD rats were randomly divided into 3 groups, sham group (n=6), I/R group (n=24) and treatment group (I/R+T, n=24). The later 2 groups were further equally divided into 3 subgroups according different time of reperfusion. Left anterior descending (LAD) coronary artery was ligated for 30 min and then released for 2 h or 24 h or 7 d in different subgroups. Five minutes before reperfusion, MG-132 at dose of 0.75 mg/kg was given intravenously in I/R+T group,but I/R group and sham group were given the same volume of normal saline. The levels of CHIP and HSP70 at mRNA and protein level were detected by real-time PCR and Western blotting respectively. The correlation between CHIP and HSP70 expression was analyzed. Results Compared with I/R groups, the mRNA levels of CHIP and HSP70 were significantly increased in I/R+T groups (P