Objective:To observe the influence of Naoxintong on expression of glucose-regulated protein 78(GRP78) and GRP94 in the striatum of rats with focal cerebral ischemic injury,so as to investigate their possible protective mechanism on cerebral ischemic injury.Methods:Ninety rats were equally randomized into 3 groups(n=30): sham operated group,ischemic group(Focal transient cerebral ischemia model was established with intraluminal occlusion of left middle cerebral artery) and Naoxintong pre-treated group(Treated with Naoxintong 5 d before ischemic injury).The expression of GRP78,GRP94 in rats striatum was detected by histological method,immunohistochemistry staining and semiquantitative RT-PCR at the different time points(6,12 and 24 h after ischemic treatment).Results:The focal transient cerebral ischemia model was successfully established in rats.Histological results showed that the degree of focal cerebral ischemic injury in Naoxintong pre-treated group was significantly lower than that in ischemic group.Immunohistochemistry staining and RT-PCR results illustrated that the expression of GRP78 and GRP94 in ischemic group was lower than that in sham operated group at each time point after ischemic treatment((P<0.01).)The expression of GRP78 and GRP94 in ischemic group and Naoxintong pre-treated group were the lowest at 6 h and the highest at 12 h,and the expression at 24 h was lower than that at 12 h but higher than that at 6 h.Compared with the ischemic group,the expression of GRP78 and GRP94 was higher in Naoxintong pre-treated group at the same time point((P<)(0.05,)P<(0.01).) Conclusion:The expression of GRP78 and GRP94 is upregulated within 12 h of cerebral ischemic injury in rats.Naoxintong can promote the expression of GRP78 and GRP94 in ischemic cerebral areas,protect the function of endoplasmic reticulum and relieve the cerebral injury caused by ischemia.