Abstract: To study the function of apoptosis-blocking proteins Bcl-2 and Bcl-xl in the neuroprotective role of ischemic preconditioning （IPC）, cerebral ischemia/Reperfusion rat model was established by using 4-vessel occlusion and repassing, the histopathological changes, the percentage of apoptosis and the expression of Bcl-2 and Bcl-xl proteins of the neurons in CA1 region of rat hippocampus with IPC were examined and detected with Nissls staining, Flow cytometry （FCM） and immunohistochemistry technique. The results showed that forebrain ischemia and reperfusion can cause apoptosis of neurons in CA1 region of hippocampus. IPC protects the neurons against the lethal ischemia/reperfusion injury by decreasing the number of apoptotic neurons, and the expressions of Bcl-2 and Bcl-xl are induced by IPC in early period of reperfusin. The results suggest that blocking the process of neuronal apoptosis after ischemic reperfusion may play an important role in the mechanism of neuroprotection induced by IPC.

Key words: Rat, Ischemia/reperfusion injury, Preconditioning, Apoptosis, Bcl-2, Bcl-xl, Hip pocampus