ABSTRACT
Objective To investigate the effect of capsaicin on cognitive function and the expression of TRPV1 protein in hippocampus of rats with chronic cerebral hypoperfusion (CCH).Methods 60 SD rats were randomly divided into control group (SHAM group),chronic cerebral hypoperfusion group (CCH group),placebo control group(PC group) and capsaicin group(CAP group) with 15 in each group.The chronic cerebral hypoperfusion rat model was established by permanent bilateral common carotid artery occlusion.The rats in CAP group and PC group were given capsaicin and saline respectively by intraperitoneal injection,twice a week.The spatial learning and memory ability and emotion of rats were observed by Morris water maze test and open field test,and the expression of TRPV1 in the hippocampus of rats was detected by Western blot.Results (1) In the open field experiment,compared with the SHAM group (22.60±4.60),the standing times of the CCH group(12.10±2.80) decreased (P＜0.01),but the standing times of CAP group (19.30± 4.16) increased compared with that of h PC group(12.50 ±2.68) (P＜0.01).(2) In Morris water maze test,positioning navigation experiment showed that compared with the SHAM group,the escape latency of the CCH group and the PC group increased (P＜0.05),while the escape latency of CAP group was shorter than that of the PC group (P＜ 0.05).And in the space exploration experiment,compared with the SHAM group (1.87 ± 0.64),the times of crossing the platform in CCH group (0.75 ± 0.89) and the PC group (1.00± 0.93) decreased,while the latency of crossing the platform increased (P＜0.01).And the times of crossing the platform in CAP group((2.38±0.74) increased compared with that of PC group,and the latency of crossing the platform of CAP group decreased compared with that of PC group (P＜0.01).(3) Results of Western blot showed that compared with the SHAM group,the level of TRPV1 in rat hippocampus of CCH group was down regulated (P＜0.05),and the expression of TRPV1 in CAP group was higher than that of PC group (P＜0.05).Conclusion Capsaicin can effectively improve cognitive impairment in rats with chronic cerebral hypoperfusion,which may be related to the up-regulation of TRPV1 protein expression in hippocampal tissues.