The Effects Of Inosine On Apoptosis And Expression Of Cyto-C And Calpain In Neurons After Cerebral Ischemia Reperfusion In Rats

Objective To investigate the effects of inosine on neuronal apoptosis and expression of Cytochrome c and Calpain mRNA after focal cerebral ischemia reperfusion in rats, to explore the neuroprotective mechanisms of Inosine in the level of apoptotic gene regulation.Methods The model of focal ischemic reperfusion in SD rats was induced by intraluminal middle cerebral artery (MCA) occlusion with a nylon monofilament suture. Inosine (10mg/kg) was injected intraperitoneally twice before and 12 hours after reperfusion. In situ hybridization was performed to examine the expression of Cytochromec and Calpain mRNA at 2,6,12h and 1,2,3,7,14d after reperfusion and in shame-operated controls . Apoptosis was also characterized by terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end-labeling(TUNEL)staining. Results Cytochromec and Calpain mRNA expression was weak in shame-operated controls and was detected in cortex and striatum of ischemic hemisphere as early as 2h after reperfusion and reached a peak at 12h and 1d in cortex and striatum respectively. Inosine treatment diminished the Cytochrome c and Calpain m RNA expression at and after 12h after reperfusion. TUNEL-positive cells were observed 2h after reperfusion in cortex and striatum and significantly peaked at 1 and 2d after reperfusion in cortex and striatum respectively, while there was no remarkable change in ischemic hemisphere and shame-operated controls at 14d after ischemia. Furthermore, Inosine decreased the number of TUNEL-positive cells at and after 12h after reperfusion.Conclusions These results indicate that Inosine attenuates ischemic neuronal apoptosis by inhibiting Cytochrome c and Calpain m RNA expression . Inosine may be a potential compound in treating stroke.