The Effects Of Picroside On Apoptosis And Gene Expressions Of Cytc And Calpain In Neurons After Cerebral Ischemia Reperfusion In Rats

Objective:To investigate the effects of picroside Ⅱ on neuronal apoptosis and gene expressions of cytochrome c (CytC) and calpain in neurons after cerebral ischemia in rats, and to explore the neuroprotective mechanisms of picroside Ⅱ.Methods:The model of focal ischemia in Wistar rats was induced by intraluminal middle cerebral artery occlusion (MCAO) with a nylon monofilament suture. Picroside Ⅱ (10mg/kg) was injected intraperitoneally2hours after cerebral ischemia. The neurological function scores were determined by Bederson’s method. Apoptosis was characterized by terminal deoxynucleotidyl transferase-mediated uridine5’-triphosphate-biotin nick end-labeling (TUNEL) staining. In situ hybridization was performed to examine the expressions of Cyt C and calpain mRNA in cortex and striatum.Results:(1) The neurological behavioral function recovered gradually from reperfusion3d, and significantly at7-14d compared with sham group.(2) TUNEL-positive cells were observed2h after reperfusion in and peaked at1and2d afte reperfusion in cortex and striatum respectively. Picroside Ⅱ decreased the number of TUNEL-positive cells at and after12h after reperfusion.(3) The expressions of CytC and calpain mRNA were weakly in shame-operated group and were detected in cortex and striatum of ischemic hemisphere as early as2h after reperfusion and reached a peak at12h in cortex and1d in striatum respectively. Picroside treatment diminished the CytC and calpain mRNA expressions at and after reperfusion12h.Conclusions:These results indicate that picroside II might promote neurological function recovery by means of inhibiting ischemic neuronal apoptosis and by inhibiting gene expression of CytC and calpain. It may be a potential compound in treating stroke.