Effects Of Castration On Exercise Induced Improvements In Cognitive Function In The Rats

Objective:To observe effects of castration on exercise’s improving cognitive function in the rats and explore the effect of serum testosterone on exercise improving cognitive function. And to explore the mechanism of the changes of serum testosterone levels in the movement.Methods:32one-month-old male SD rats were randomly divided into4groups:A group (castrated model and exercise group),B group (castrated model and non-exercise group),C group (sham operation and non-exercise group) and D group (sham operation and exercise group). The rats of group A and group B were castrated. And a week later, the rats of group A and group B were trained in the treadmill at the velocity of25m/min for thirty minutes,once daily for6days a week. After4weeks, the rats of4groups were given the Morris water maze test to compare the spatial memory ability. The blood samples of all the rats were collected after the Morris water maze test and the levels of serum testosterone were detected. The Leydig cells of the rats in group C and group D were stimulated by equal amount of human serum samples in order to compare the reactivity of the Leydig cells in rats of different goups. The rats serum samples were used to stimulate the same of Leydig cells in two another rats in order to compare the bioactivity of the serum LH in rats of different goups.Results:(1) Morris water maze test (using analysis of variance of factorial design) showed that exercise on the spatial memory test of rats had an effect (P<0.05). Castration on the spatial memory test of rats had an effect (P<0.05). There is the interaction between castration and exercise on cognitive function (P<0.05).(2) Compared with group C, the reactivity of the Leydig cells in rats of goups D is obviously enhanced (P<0.01).(3) Compare the bioactivity of the serum LH in rats of different goups (using analysis of variance of factorial design), exercise on the bioactivity of the serum LH in rats had an effect (P<0.05) and castration on the bioactivity of the serum LH in rats had an effect (P< 0.05). There is no interaction between castration and exercise on the bioactivity of the serum LH in rats (P>0.05).(4) The result of the levels of serum testosterone in rats of four groups (using analysis of variance of factorial design) showed that exercise on the levels of serum testosterone in rats had an effect (P<0.01), castration on the levels of serum testosterone in rats had a statistically significant effect (P<0.01) and there is the interaction between castration and exercise on the levels of serum testosterone (P<0.01).Conclusions:Exercise can improve cognitive function in SD rats and increase the levels of serum testosterone. Castration can decline cognitive function and restrain the effect of exercise improving cognitive function in SD rats.These results showed that the increasing of the levels of serum testosterone was one of mechanisms of exercise improving cognitive function. Exercise can enhance the reactivity of the Leydig cells and the bioactivity of the serum LH in SD rats,which were the mechanisms of exercise increasing the levels of serum testosterone.