Cystamine Treatment Affects The Expression Of Nucleophosmin In The Hippocampus After Global Cerebral Ischemia In Rats

Objective To observe the expression of NPM in hippocampus following the global cerebral ischemia in rats, and the treatment effect of cystamine on NPM, to explore the neuro-protection mechanisms of cystamine.Methods The experimental GI model was established by 4-vessel occlusion method and confirmed successfully by an electroencephalogram (EEG).78 adult male Sprague-Dawley rats(the model achievement ratio 75% and extra rats were supplemented),about280-320g,were randomly divided into sham group (n=6), global cerebral ischemia group(GI, n=36) and global cerebral ischemia+CYS treatment group (GI+CYS, n=36), and the two latter groups were randomly divided into 6h,12h, 1d,3d, 5d and 7d time points after ischemia-reperfusion, each subset with 6 rats. CYS(150mg/kg/day)were administered to rats in GI+CYS group by abdominal cavity injection one time a day. Cystamine was given only one time within 24h. The rats in sham group were treated with lml saline by abdominal cavity injection one time a day and sacrificed by decapitation 3 days later. The rats in GI group were treated with 1 ml saline by abdominal cavity injection one time a day. The rats were sacrificed by decapitation after anesthesia, the cerebral hippocampus tissues were obtained at 3 days after sham operation in sham group and at 6h,12h,1d,3d,5d and 7d time points after the global cerebral ischemia-reperfusion in GI and GI+CYS groups.The expression of NPM in the hippocampus after global cerebral ischemia in rats was detected by WESTERN BLOT. The ratio of the gray scale of the electrophoresis bands was analyzed by ImageJ.All data were presented as mean±standard deviation (SD). Data analysis were performed using SPSS 11.5 statistical software.A P value less than 0.05 was considered statistically significant.Results WESTERN BLOT:Using the antibody to NPM to make immunity detect of the samples via SDS-PAGE and trarsmembrane.Using ECL coloration,a single protein band of molecular weight 37kD is detected. The expression of NPM is shallow in the sham group. In the GI group,the expression of NPM in subset 6h is less than that in the sham group, it grows up in subset 12h and comes to the peak in subset 1d and keep high expression in subset 3d,5d.Compared to the sham group, the expression of NPM in the injured hippocampus in subset ld,3d,5d of GI group is significantly increased (p<0.05).In the GI+CYS group, the expression of NPM begins to grow up in subset 6h,and comes to the peak in subset 1d and keep high expression in subset 3d.5d and 7d. Compared to the corresponding subsets of GI group, the expression of NPM in subset ld,3d,5d,7d of GI+CYS group are significantly higher(P＜0.05). Compared to the GI group, the expression of NPM in subset 12h of GI+CYS is higher(P>0.05).β-Actin(42KD) shows no significant difference of the quantity of the sham group, GI group and GI+CYS group.Conclusion Global cerebral ischemia can induce the up-regulation of NPM,which protect injury neuron by initiating cell signal transmission pathway and producing effector molecule. CYS can significantly increase the expression of NPM in hippocampus after GBI, which might be one of the mechanisms of the protective effects of CYS on the neurons.