Effects of dexmedetomidine preconditioning on myocardial expression of high mobility group box-1 protein during myocardial ischemia/reperfusion injury in rats

Abstract

Objective To investigate the effects of dexmedetomidine(Dex) preconditioning on myocardial expression of high mobility group box-1 protein (HMGB1) during ischemia/reperfusion(I/R) injury in rats. Methods Fifty-two healthy male SD rats, weighing 250-300 g, were randomly divided into 4 groups(n=13): group sham operation(group S), group I/R, group Dex+I/R(group D), group Dex+yohimbine+I/R(group D/Y). In group I/R, group D and group D/Y, myocardial I/R was produced by occlusion of left coronary anterior descending artery for 30 min followed by 120 min reperfusion. Blood samples were taken for detecting the concentration of IL-6 and TNF-α by ELISA at the end of reperfusion. The rats were then killed, and the heart was removed for measuring infarct size and area at risk using 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. Myocardial HMGB1 expressions were measured by Western blot analysis. Results Compared with group S, the levels of IL-6[(336±41) ng/L], TNF-α[(636±25) ng/L] in serum and the IS/AAR ratio were significantly increased, the expression of HMGB1 were also significantly increased in group I/R(P 0.05). Conclusions Dex preconditioning decrease the expression of HMGB1 and alleviate inflammatory response during myocardial ischemia/reperfusion injury(MI/RI) in rats, which might be a result of the α2 adrenergic receptor stimulation. Key words: Dexmedetomidine; Preconditioning; myocardial ischemia/reperfusion injury; High mobility group box-1 protein; Rat