Objective: To investigate the effects of ligustrazin on the activities of
succinate dehydrogenase (SDH) and
cytochrome oxidase
(CCO) in the myocardial mitochondria in ischemia_reperfusion rats. Methods: The models of myocardial ischemia_reperfusion injury were produced by coronary artery ligation. The rats were divided into the sham-operating control (SC), ischemia_reperfusion (IR) and ischemia_reperfusion preconditioned with ligustrazin (IR+L) group. The activities of SDH, CCO, superoxide dismutase (SOD) and glutathione peroxydase (GSH.Px) and the contents of malondialdehyde (MDA), Cytaa 3, Cytc and phospholipid (PL) were determined respectively. Results: The activities of SDH and CCO in IR group were significantly depressed in contrast with SC group. The activities of SDH and CCO in (IR+L) group were higher than in IR group (P<0.01), and were the same for SC group. Compared with IR group, the activities of SOD and GSH.Px were higher and the content of MDA was attenuated in (IR+L) group. Conclusions: Ligustrazin can prevent the reduction of the activities of SDH and CCO in the myocardial mitochondria in ischemia_reperfusion rats, which may be due to scavenging oxygen free radicals and its anti_lipid peroxidation reaction.