Abstract:

Abstract:Objective
To explore the influence of different intensities of exercise load on the expressions of  nerve growth factor(NGF)and  neuronal nitric oxide synthase (n-NOS) in rat hippocamp tissues  and mechanism and lay a foundation for study on prevention of brain diseases.Methods 40 Wistar male rats were divided into non-exercise group (control group) and exercise group. In exercise group,the  rats swam for  15,30 and 60 min  every day. After 8 weeks,the rat brain was obtained, the expression levels of NGF and n-NOS in rat hippocamp tissues were detected with S-P immunohistochemistry.Results  Compared with control group, the positive expression levels of  of  NGF in rat hippocamp tissues  in 15,30,and 60 min groups were significantly increased (P<0.05,P<0.01).Compared with 15 min group,the positive expression levels in 30 and 60 min groups  were increased (P<0.01);but there was no significant different  between 30 min group and 60 min group(P>0.05).Compared with control  group,the nNOS positive expression levels in  rat hippocamp tissues in 30 and 60 min groups were significant increased （P<0.01）. Compared with 15 min group,the nNOS positive expression levels in   rat hippocamp tissues in 30 and 60 min groups were significantly in creased （P<0.05,P<0.01），and there was significant difference between 30 min group and 60 min group（P<0.01）.Conclusion The expression levels of  NGF and nNOS in rat hippocamp tissues are  increased  with the increase of exercise load within a certain range.It indicates that the NGF and nNOS in different periods with excise load have important effects on  in the growth and repair of hippocampal nerve.

Key words: exercise load；hippocamp；nerve growth factor；nitric oxide synthase