【Abstract】 Objective To investigate the protective effects of propofol on the brain in ischemia-reperfusion (I/R) injury rats and the underlying mechanism. Methods 65 male Wistar rats weighting 250-300g were randomly divided into 5 groups ( n = 13 ) : group S sham operation; group I/R; group P1 propofol ( 0.5mg/ kg /min ) + I/R; group P2 propofol (1.0mg/ kg /min) + I/R and group P3 propofol (1.5mg/ kg /min) + I/R. I/R group was induced by occlusion of bilateral common carotid arteries combined with controlled hypotension for 10 min. In group P1、P2 and P3, propofol was continued intravenous infusion for 60 min before I/R. The neurological behavior was evaluated at 6 h, 24 h, 48 h, 72 h, 4 d, 5 d, 6 d and 7 d after I/R. Rats were killed at 7d in each group and the brains were removed for pathomorphologic examination of the survived pyramidal neurons in the area of CA1 hippocampus. Flow cytometric was applicated for detection apoptosis at 24h of reperfusion in each group. Results Ischemic reperfusion in rats appeared behavioral defects, the animals behavior significantly better in group P2 and in group P3 than that of in group P1 and in group I/R. The HG scores of normal neurons in CA1 of hippocampus in S group, I/R group, P1 group, P2 group, P3 group was 0, 2.8±0.4, 2.6±0.5, 2.0±0.7, 1.4±0.5, respectively. The apoptosis rates in S group, I/R group, P1 group, P2 group, P3 group was 6.5%±0.6%, 51.5%±2.8%, 48.2%±0.6%, 24.7%±1.2%, 18.6%±0.8%, respectively. Conclusions Propofol has dose-dependent protection of the brain against I/R injury, and this effect may be involved in the anti-apoptosis effect of propofol.