Study Of GRP78 And CHOP On The Neuronal Apoptosis After Subarachnoid Hemorrhage In Rat

Objective:study the expression levels of endoplasmic reticulum stress factor CHOP and GRP78 and the effects of CHOP and GRP78 in early brain injury after subarachnoid hemorrhage. Through the observation of expression of CHOP and GRP78 in rats after subarachnoid hemorrhage in hippocampus neuron, analyzed the relationship between the expression of CHOP and GRP78 and neuronal apoptosis, and discussed the effect of apoptosis in early brain injury after subarachnoid hemorrhage. To provide the oretical basis for potential therapeutic targets in the future in early brain injury after subarachnoid hemorrhage. Methods:78 male Sprague-Dawley rats were randomly assigned to the control group(n=6), the sham operation group(n=36)and the experimental group(n=36). On 1h、6h、12h、24h、48h、72h,neurological scores were evaluated by a scoring system reported by Garcia et al,and HE staining, MASSON staining was used to identify the model.The morphological change of neurons were observed under the transmission electron microscope and the light microscope. The apoptotic cells were detected for by terminal deoxynucleotidyl transferase-mediated d UTPnickend labeling(TUNEL) method. The expression levels of GRP78 and CHOP were identified by western blotting. Results:Compared with the control group and the sham operation group, scores were significantly decreased in the experimental group(P<0.05). The rats in group SAH showed a large amount of blood in subarachnoid, HE and MASSON staining observed a large number of red cell accumulation in subarachnoid;The time-related rules of the expression and distribution of CHOP and GRP78 were identified by immunohistochemistry study. Electron microscope evidence showed that the ultrastructure structures of hippocampal neurons were observed in the different time points. TUNEL staining showed that the rats in the control group and the sham group displayed rare apoptotic cells in hippocampus. The number of the positive cells started increasing in 6h(P<0.01), getting to peak value in 24 h, then gradually decreasing from 48h(P<0.01) to 72 h. Few apoptotic cells were observed in 72 h.The protein levels of CHOP detected by western blotting were rising gradually from 6h(P<0.01), getting to peak value in 24 h, then gradually declining to 72 h. The levels obviously decreased were higher than the control group in 48h(P<0.01) and the levels were recovered the levels of per-operation in72 h, The protein levels of GRP78 detected by western blotting were rising gradually from 1h(P<0.01), getting to peak value in 12 h, then gradually declining to 72 h,the levels decreased were higher than the control group in 72h(P<0.01).The protein levels of CHOP detected by western blotting and the positive apoptosis cells detected by TUNEL were indicated the positive correlation(r=0.933, P<0.01). Conclusion:The expression levels of CHOP and GRP78 are regular in the early stage after subarachnoid hemorrhage. CHOP and GRP78 play in important role in inducing cells apoptosis of endoplasmic reticulum stress after subarachnoid hemorrhage.