Effect of alpha-lipoic acid on cardiomyocyte apoptosis following renal ischemia-reperfusion injury in rats

Objective To evaluate the effect of alpha-lipoic acid (ALA) on cardiomyocyte apoptosis following renal ischemia-reperfusion injury(RIRI) in rats.Methods Thirty-six male SD rats weighing 250-280 g were randomly divided into 3 groups ( n =12 each): group sham operation (group S) ; group I/R and group I/R + ALA ( group L).The model of RIRI was produced by occlusion of renal artery and vein for 45 min followed by 24 h reperfusion,in group S the renal pedicles were exposed but not occluded.In group L ALA infusion (30 mg/kg) was given via tail vein at 20 mln before ischemia and at 20 min before reperfusion,while in group I/R the equal volume of solution (35％ polyethylene glycol + 60％ physiological saline + 5％ ethanol) was infused instead of ALA.The animals were saerificed at the end of 24 h of reperfusion,blood samples were taken for detecting concentrations of serum creatinine (Cr) and malondialdehyde (MDA).Then the hearts were immediately removed for determination of SOD activity,MDA content,cardiomyocyte apoptosis (flow cytometry) and Bcl-2/Bax ratio (immunohistology).Results Serum Cr concentration,serum and myocardium MDA levels and cardiomyocyte apoptosis were significantly increased after RIRI in groups I/R and L as compared with group S ( P ＜ 0.05).ALA treatment significantly decreased serum Cr concentration,serum and myocardium MDA levels,cardiomyocyte apoptosis and increased SOD activity and Bcl-2/Bax ratio ( P ＜ 0.05).Conclusion ALA can attenuate myocardium injury by inhibiting cardiomyocyte apoptosis following RIRI in rats. Key words: Thioctic acid;  Kidney;  Reperfusion injury;  Myocardium ;  Apoptosis