Effects of Aerobic Exercises on Synaptic Plasticity and Expression of PDE-4 in Hippocampus during the Aging Process of Rats / 中国运动医学杂志

ABSTRACT

Objective To explore the effect of aerobic exercises on synaptic plasticity and expression of PDE-4 in hippocampus during the aging process of rats.Methods Forty-five adult male SpragueDawley rats were randomly divided into a control group(group C),an D-galactose induced aging group (group A) and an D-galactose induced aging & aerobic exercise intervention group(group AE).All rats were induced aging for 6 weeks and group AE was given swimming exercise intervention of a moderate load simultaneously.Then Nissl's staining was conducted to observe the neurons in the dentate gyrus(DG).The immunofluorescence was employed to detect the number and density of synaptophysin (Syp) and metabotropi glutamate receptor 1(mGluR1).And the expression level of Phos-phodiesterase 4(PDE-4) mRNA and protein was observed using the,real-time PCR and Western blotting.Results Compared with group C,senile signs such as mental retardation,lethargy and tardy movement,significantly less neurons in the hippocampus,bigger cell spacing and shallower Nissl body in the cytoplasm were observed in group A.The integrated optical density(IOD) values of Syp and mGluR1 in group A decreased significantly compared to group C(P＜0.01),while those of group AE were significantly higher than group A(P＜0.01).The expression of PDE-4 mRNA and protein in Group A increased significantly compared with group C (P＜0.01),but that of group AE was significantly lower than group A (P＜ 0.01).The expression of PDE-4 mRNA was negatively correlated to the IOD value of Syp and mGluR1 (P＜0.01,P＜0.05).Conclusions The aerobic exercises can improve the morphology of hippocampal neurons and keep the number and density of Syp and mGluR1 at a certain level to maintain the synaptic plasticity,so as to improve brain function and delay the aging process.Moreover,exercise may affect brain function through down-regulating the expression of the PDE-4 gene.