Abstract: AIM: To examine the effects of the gingkgolide combined with insulin treatment on the learning ability of the AD-like model rats and explore the possible mechanism of its effect.METHODS: The AD-like animal models were established by injection of okadaic acid( OA) in the hippocampal CA1 area, and pretreatment was administered by injecting insulin in the lateral brain ventricle and forced feeding with gingkgolides.The learning capability of the rats was examined by means of Morris water maze, and the expressions of neurofibrillary tangle(NFT) and glial fibrillary acidic protein ( GFAP) in the CA1 area were observed through Bielschowsky-dyeing and immunohistochemistry, respectively.RESULTS: The impaired learning ability of the rats in the gingkgolide combined with insulin grouPwas greatly improved compared with that in the grouPtreated with gingkgolide alone( P<0.05).Meanwhile, the expressions of GFAPand NFT in the CA1 area in the gingkgo grouPand gingkgo combined with insulin grouPwere significantly reduced,and even lower in the combined grouPthan in the gingkgo grouP( P<0.05).CONCLUSION: The gingkgolide combined with insulin treatment exerts a stronger improving effect on the learning ability of the AD-like model rats, possibly by reducing phosphorylation of Tau in neurons and inhibiting hyperplasia of the glial cells in the hippocampal CA1 area.

Key words: Alzheimer disease, gingkgolide, insulin, glial fibrillary acidic protein, neurofibrillary tangle, hippocampus