Expressions Of ASK1 And C-jun Protein And The Effects Of Ganglioside GM1 On Their Expressions After Focal Cerebral Ischemia Reperfusion And Their Roles In Neuronal Apoptosis In Rats

Objective We study the expressions of ASK1 and c-jun protein and the effects of ganglioside GM1 on their expressions as well as their roles in neuronal apoptosis after Focal Cerebral Ischemia Reperfusion in rats , to explore molecule-mechanism and pathomechanism of cerebral ischemia reperfusion injury and to provide experimention foundation for clinical treatment.Methods The middle cerebral artery occlusion(MCAO) models were established by using the intraluminal suture occlusion method in Sprague-Dawley(SD) rats. Fifty-six SD rats were randomly divided into four groups , normal group, sham operation group, cerebral ischemia reperfusion group, and GM1 treatment group. Rats of treatment group were celio-injected GM1 according to the dose of 20mg/kg before experiment and everyday after that. We obtained brain tissue at the time of 0.5h,3h,6h,1d,3d,7d after ischemia reperfusion (IR). Pathologic changes were evaluated by Hematoxylin and Eosin stain. The expressions of ASK1 and c-jun protein were detected by immunohistochemistry, and the neuronal apoptosis in ischemia reperfusion rat brains were evaluated by TUNEL assay. Experimental results were comparatively analyzed with statistic soft package of Spssl2.0.Result Experimental results revealed that ASK1 and c-jun protein were fewly expressed in endochylema and nucelus of neurons and gliacytes of brain tissue in normal rats . There was no significant difference between the normal group and sham operation group (P> 0.05). In ischemic zone including ischemic penumbra and ischemic core zone of cerebral ischemia reperfusion group and GM1 treatment group, the ASK1 positive neurons firstly detected 0.5 hour after reperfusion, and reacheded peak at 3 hours (P<0.01), and appeared secondary peak on the 3rd day (P<0.01), then declined quickly after that , still to remain small amounts expressions at 7 days. While the c-jun positive neurons firstly detected 0.5 hour after reperfusion, reacheded peak at 6 hours (P<0.01), and appeared secondary peak on the 3rd day (P<0.01). Compared with in the ischemic core zone , the expressions of ASK1 and c-jun protein in the ischemic penumbra were evidently increased (P<0.01). Compared with of cerebral ischemia reperfusion group, the expressions of ASK1 and c-jun protein of GM1 treatment group were evidently decreased (P<0.01). Correlative analysis showed that there was positive correlation between the expressions of ASK1 and c-jun .The amount of apoptosis cells in ischemic zone of cerebral ischemia reperfusion group and GM1 treatment group reaches the peak in ischemic reperfusion 3～6 hours (P<0.01). Compared with in the ischemic core zone , the amount of apoptosis cells in the ischemic penumbra were evidently increased (P<0.01). Compared with of cerebral ischemia reperfusion group, the amount of apoptosis cells of GM1 treatment group were evidently decreased (P<0.01). Correlative analysis showed that the expressions of ASK1 and c-jun protein were positive correlation with apoptosis cells (P <0.01).Conclusion1. The expressions of ASK1 and c-jun protein are up-regulated after focal cerebral ischemia reperfusion. The expressions of ASK1 and c-jun protein are correlation with neuronal apoptosis.2. Exogenous gangliosides (GM1) take neunoprotective effect by down-regulatating the expressions of ASK1 and c-jun protein and refraining neuronal apoptosis.