Effect of picroside II on mitochondria cytochrome C expression and its significance in rats after ischemia/reperfusion

Abstract

Objective To investigate the effect of picroside II on mitochondria cytochrome C (CytC) expression and its significance in rats after ischemia/reperfusion. Methods Ninety-six Wistar rats were randomly divided into sham-operated group, model group, picroside II group, Cyclosporin A (CsA, specific antgonist of CytC) group, CsA+picroside II group, atractyloside (Atr, selective agonist of CytC) group, Atr+picroside II group and DMSO group(n=12); the middle cerebral artery occlusion/reperfusion models referring to Longa's method with medications were adopted, which were established by inserting a monofilament suture into the internal carotid artery for 2 h and then reperfusion for 24 h. After 24 h of ischemia/reperfusion, modified neurological severity scale (mNSS) scores were observed, contents of reactive oxygen species (ROS) in brain tissues were measured by enzyme-linked immunosorbent assay (ELISA), morphology of brain tissues was observed by hematoxylin-eosin staining, ultrastructures of mitochondria were observed by transmission electron microscopy, apoptotic cells were counted by terminal deoxynucleotidyl transferase dUTP nick end labeling assay (TUNEL), and CytC expression was determined by immunohistochemical assay and Western blotting. Results As compared with the sham-operated group, the model group had significantly increased mNSS scores, ROS contents, number of apoptotic cells and CytC expression (P<0.05), and the mitochondria structurewas seriously destroyed. The picroside II group had obviously decreased mNSS scores, ROS contents, number of apoptotic cells and CytC expression, and the morphology of brain tissue was improved and the mitochondria damage was reduced as compared with the model group, with significant differences (P<0.05). The Atr+picroside II group had significantly decreased mNSS scores, ROS contents, number of apoptotic cells and CytC expression (P<0.05), and the mitochondria damage in the Atr+picroside II group was reduced as compared with that in the Atr group with significant difference(P<0.05). Conclusion The mechanism of picroside II protecting against focal cerebral ischemia reperfusion might attribute to decrease of ROS contents, protection of mitochondria structure and down-regulation of CytC expression in middle cerebral artery occlusion/reperfusion rats. Key words: Picroside II; Ischemia/reperfusion; Mitochondria; Oxidative stress; cytochrome C