Effect of estrogen on cell apoptosis and Bcl-2 expression in rat focal cerebral ischemia tissue after ovariectomy

Aim: To study the effect of estrogen on cell apoptosis and Bcl-2 expression in rat focal cerebral ischemia tissue. Methods: A total of 30 female Wistar rats that were removed bilateral ovaries were randomly divided into three groups: sham operation group, operation control group, estrogen treatment group with 10 rats in each group.Focal cerebral ischemia model was induced by the middle cerebral artery occlusion (MCAO) for 2 hours. All animals were killed at 24 hours of reperfusion. Cell apoptosis was detected by TUNEL staining. The expression of Bcl-2 was determined using immunohistochemistry. Results: Sham operation group did not find infarction focus.Infarction volume were reduced significantly in estrogen treatment group(59.32±8.95)mm~3 compared with operation control group (96.93±11.63)mm~3 (P0.05). Apoptosis cell reduced significantly in estrogen treatment group (96±12) and compared with operation control group ( 126± 9) (P0.05). However, expression of Bcl-2 in estrogen treatment group increased (P0.05).Conclusion: Eestrogen could increase the expression of Bcl-2 in cerebral ischemia tissue and inhibit the neuronal cell apoptosis.The neuroprotective mechanism of estrogen may be assiociated with the up-regulation of Bcl-2.