Effect of exercise preconditioning on nerve growth factor and learning-and-memory abilities in rats suffered from focal cerebral ischemia / 中华行为医学与脑科学杂志

ABSTRACT

Objective To investigate the effect of exercise preconditioning on the expression of nerve growth factor(NGF) and its receptor TrkA as well as learning-and-memory abilities in rats suffered from focal cerebral ischemia.Methods Thirty-six male SD rats were randomly divided into sham operation group (Sham-MCAO,n=12),focal cerebral ischemia-reperfusion group (MCAO,n=12) and exercise preconditioning + cerebral ischemia-reperfusion group (EX+MCAO,n=12).Rats in EX+MCAO group were placed in the treadmill device and accepted 4 weeks exercise training.Then method of middle cerebral artery occlusion was applied to prepare transient focal cerebral ischemia reperfusion model.Garcia's method was used to assess the neural function in rats.Western blotting was applied to test the expression of NGF and TrkA protein in the successfully established experimental MCAO rats.Morris water maze experiment was uti lized to test the learning-and-memory abilities of the rats.Results (1) Compared with Sham-MCAO group,the expression of NGF in rats' brain tissue was lower in MCAO group (cerebral ischemia 1h reperfusion 24h) (P＜0.05).The expression of NGF of EX+MCAO group was higher than that of MCAO group,but still lower than that of Sham-MCAO group (P＜0.05).(2)The expression of TrkA in rats' brain tissue was higher in MCAO group compared with Sham-MCAO group (P＜0.05).Compared with MCAO group,the expression of TrkA was even higher in EX+MCAO group (P＜0.05).(3)On the fifth day in the Morris water maze test,the latency of MCAO group was significantly longer than that of Sham-MCAO group((9.36± 1.18)s vs (4.86± 1.52) s,P＜0.05).However,compared with MCAO group,the latency in EX+MCAO group ((6.02± 1.04) s) was shorter,but still longer than Sham-MCAO group (P＜0.05).There was no significant difference among the three groups in the average swimming speed (P＞0.05).Conclusion Exercise preconditioning can up-regulate the expressions of NGF and TrkA protein,which can also improve the learning-and-memory abilities in rats suffered from focal cerebral ischemia reperfusion injury.