Effect of ERK inhibitor PD98059 on expression of Caspase-3 in hippocampus of SD rats after global cerebral ischemia/reperfusion

Objective To investigate the effect of extracellular signal-regulated kinase(ERK) inhibitor on expression of Caspase-3 in hippocampus after global cerebral ischemia/reperfusion in SD rats,and to explore the role of ERK in global cerebral ischemia/reperfusion injury.Methods Ninety healthy male SD rats were randomized into 3 groups:sham group(n=30),ischemia/reperfusion group(IR group,n=30) and PD98059 group(PD group,n=30).Global cerebral ischemia/reperfusion model was established by 4-vessel occlusion method.HE staining,immunohistochemical staining and TUNEL staining of brain tissue section were performed after reperfusion for 2,6,12,24,48,72 h.Cellular morphology,apoptosis index and expression of ERK and Caspase-3 in CA1 of hippocampus were observed and detected after reperfusion for 2,6,12,24,48,72 h.Results Cellular damage in PD group was weaker than that in IR group by HE staining.Immunohistochemical results showed that the expression of P-ERK in CA1 of hippocampus in PD group was significantly lower than that in IR group at 12-72 h after reperfusion(P0.05),and the expression of Caspase-3 in CA1 of hippocampus in PD group was also significantly lower than that in IR group at each time point.Apoptosis index in PD group was lower than that in IR group at each time point by TUNEL staining(P0.05).Conclusion PD98059 could inhibit the expression of ERK and Caspase-3 in CA1 of hippocampus and decrease the apoptosis after global cerebral ischemia/reperfusion injury,which suggests that ERK may participate in the global cerebral ischemia/reperfusion injury.