RESUMO
Objective To investigate the effect of curcumin on apoptosis in hippocampal neurons and the expression of c-Jun N-terminal kinase 3 (JNK3) and postsynaptic density protein 95 (PSD95) in hippocampus during cerebral ischemia-reperfusion (I/R) in rats with spontaneous hypertension (SH) .Methods One hundred and thirty-five male rats (homologous with WKY) with SH and 90 male normotensive WKY rats, weighing 275-325 g,were used in this study. The WKY rats were randomized into 2 groups ( n = 45 each) : sham operation group (WS group) and cerebral I/R group (W-I/R group) . The rats with SH were randomly divided into 3 groups ( n = 45each) : sham operation group (S-S group), cerebral I/R group (S-I/R group) and curcumin group (S-C group) .Global cerebral ischemia was produced by 4 vessel-occlusion method. The bilateral common carotid arteries were only exposed but not ligated in W-S and S-S groups. Intraperitoneal corn oil 10 ml/kg was injected at 30 min of reperfusion in W-I/R and S-I/R groups. Intraperitoneal curcumin 100 mg/kg was injected at 30 min of reperfusion in S-C group. Three animals in each group were sacrificed at 2 h, 6 h, 1 d, 3 d and 7 d of reperfusion and their brains were harvested for determination of apoptosis in hippocampal neurons and the expression of JNK3 and PSD95in hippocampus. Results The number of apoptotic neurons was significantly increased in S-S group compared with W-S group ( P < 0.05) . The number of apoptotic neurons was significantly increased and the expression of JNK3was up-regulated in S-I/R group compared with S-S group ( P < 0.05) . The number of apoptotic neurons was significantly decreased and the expression of JNK3 was down-regulated in S-C group compared with S-I/R group (P <0.05) . There was no significant difference in the expression of PSD95 among all the groups ( P > 0.05) . Conclusion Curcumin can inhibit apoptosis in hippocampal neurons and the mechanism is related to down-regulation of the expression of JNK3 in hippocampus. The mechanism by which curcumin down-regulates the expression of JNK3in hippocampus may not be related to PSD95 pathway.
