Abstract: Objective: Aging SD rats induced by injection of D-Galactose were intervened by aerobic exercise ahead of aging and during aging to explore the effect of aerobic exercise on brain aging and expression level of NCAM in frontal lobe. Methods: 60 3-month-old male SD rats were randomly divided into groups SD(aerobic exercise ahead of aging group), ND(aging group), NNa(saline control group) and NDs(aerobic exercise during aging group), n=15. SOD activity, GSH-Px activity and MDA contents in cerebral cortex were determined. Expression level of NCAM in frontal lobe was determined by real-time PCR, western blotting and immunohistochemistry. Results: Group ND, compared with group NNa rats, revealed a lot of obvious aging signs, such as lethargy, loss of appetite, slowness, curly brown hair and shedding; SOD and GSH-Px activity of group ND rats were significantly lower than group NNa(P<0.01), MDA content was significantly more than that of group NNa(P<0.01), SOD and GSH-Px activity and MDA content of group ND rats had no significant difference from group ND(P>0.05), SOD and GSH-Px activity of group NDs rats were very significantly higher than those of group ND(P<0.01), MDA content was significantly less than that of group ND(P<0.01); mRNA and protein expression level of NCAM gene in frontal lobe of group ND rats were significantly lower than those of group NNa(P<0.01). Compared with group ND, mRNA and protein expression level of NCAM gene in frontal lobe of group SD rats had no significant difference (P>0.05) while mRNA and protein expression level of NCAM gene in frontal lobe of group NDs rats were significantly higher than those of group ND(P<0.01. Immunoreactivities of NCAM in frontal lobe were brown, mainly located in neuronal cytoplasm beside the granular cells. Conclusion: Injection of D-galactose induced brain aging model rats successful; Aerobic exercise ahead of aging did not have a favorable impact on brain aging and aerobic exercise during aging showed an effective impact on delaying brain aging; Aerobic exercise ahead of aging did not have a favorable impact on expression level of NCAM in frontal lobe and aerobic exercise during aging could significantly increase expression level of NCAM in frontal lobe.

Key words: aerobic exercise, aging, neural cell adhesion molecule, frontal lobe, real-time PCR, Western blotting, immunohistochemistry, rat