Abstract: Objective To study the protective effects of soybean isoflavone and soybean isoflavone coordinated with folic acid on cultured glial cells damaged by cyclophosphamide.Methods Cultured glial cells from new born ICRmice were exposed to cyclophosphamide in the presence of S9, a metabolic activator of cyclophosphamide.In order to evaluate the protective effectiveness of soybean isoflavone, folic acid and their combinative effect, the single-cell gel electrophoresis(SCGE, comet assay) and MTTassay were performed.Results Comparing to model group, the tail length of nuclear DNAand the percentage of comet-like tail glial cells were significantly reduced in solo-soybean isoflavone, solo-folic acid and soybean isoflavone coordinated with folic acid group, and the reducing effects of co-administration were more efficiency than solo-administration, but not significantly(P=(0.052)).Comparing to model group, the activity of glial cells was significantly increased in solo-soybean isoflavone, solo-folic acid and soybean isoflavone coordinated with folic acid group.Especially, the glial cell activity of co-administration group was significantly increased comparing to solo-administration(P<0.05).Conclusion Soybean isoflavone and folic acid are the protective factors of nervous system, and the protective action of co-administration would be more efficiently than solo-administration and the protective effects were dose-dependent.

Key words: soybean isoflavone, folic acid, cyclophosphamide, neuro-protection, glial cells