Abstract: Objective To explore the effect of extracellular regulated protein kinases (ERK) signaling pathway on early brain injury and autophagy of nerve cell in hippocampus area in rats with subarachnoid hemorrhage (SAH). Methods Forty-eight adult male Sprague-Dawley rats were randomly divided into sham group, SAH group, SAH+dimethyl sulfoxide (DMSO) group and SAH+U0126 group, with 12 rats in each group. The SAH model was established with puncture of internal carotid artery. The SAH+U0126 group was injected with U0126 0.05 mg/kg; the sham group and SAH group were injected with normal saline, and the SAH+DMSO group was injected with DMSO 30 minutes before modeling. They were sacrificed 24 hours after modeling. The brain water content was measured with wet and dry method. The morphology changes of neural cells in hippocampus CA1 were observed by HE staining. The expression of phosphorylation ERK (p-ERK), Beclin-1 and LC3-Ⅱ were detected with immunohistochemical method and Western blotting. Results Compared with the sham group, the brain water content increased (P<0.05), the number of survival neurons decreased (P<0.05), the expression of p-ERK, Beclin-1 and LC3-Ⅱ increased in SAH group (P<0.05). Compared with SAH group, the brain water content increased, the number of survival neurons decreased (P<0.05), the expression of p-ERK, Beclin-1 and LC3-Ⅱ decreased in SAH+U0126 group (P<0.05); and no significant difference was found in SAH+DMSO group (P>0.05). Conclusion The activation of ERK signaling pathway may alleviate early brain injury after SAH by regulation of autophagy.

Key words: subarachniod hemorrhage, early brain injury, autophagy, extracellular regulated protein kinases, rats