Abstract: AIM: To study the neuroprotective effect and molecular mechanism of progesterone on reperfusion injury following ischemia.METHODS: The rats with transient middle cerebral artery occlusion (MACO) was described by Zea-longa for 2 h and reperfusion for 24 h. 48 male rats were divided randomly into 6 groups that were the sham, ischmia/reperfusion (I/R), dimethl sulfoxide (DMSO), and posttreatment, pretreatment, pre + posttreament with PROG groups.The immunohistochemistry staining and TUNEL reaction were used to facilitate the quantities of p53 protein and apoptosis in the brain tissuses.RESULTS: There were 26.25±3.54 cells in p53 immunostaining in the I/R group, 22.88±3.52 cells in DMSO group, 15.00±2.07 cells in the pretreatment group, 16.75±2.60 cells in the posttreatment group, and 10.38±1.69 cells in the pre and posttreament group.The number of apoptosic cells was 1.88±0.25 in the sham group, 41.38±3.85 in the I/R group, 38.13±5.69 in the DMSO group, 22.88±2.70 in the pretreatment group, 25.63±2.93 in the posttreatment group, and 20.88±2.30 in the pre + posttreament group.The difference among drug management groups (pretreament, posttreament, and pre +posttreament) and control groups(I/R, DMSO) was significant (P <0.05).CONCLUSION: PROG may protect the ischemia brain on reperfusion injury.Reducing the expression of p53 protein and apoptosis would be one of the molecular mechanism.

Key words: progesterone, ischemia, reperfusion injury, apoptosis, p53