Abstract:

Objective   To determine the pathologic effects of ethanol soluble extract of polygala on the growth of new born neurons in hippocampus and the formation of neurofibrillary tangles(NFT) and senior plaques(SP) in both normal and Alzheimer′s disease(AD) mice,together with the detection of its effects on oxidative stress and Aβ40, Aβ42 in the mice brain in normal and AD mice. Methods   9-month mice devided by sex were used to generate the AD mice as the pathological group together with normal mice at the same age as the normal group, both contain female and male mice. Placebo group (control) and drug treatment group were divided in both groups, totally 4 groups. Immunohistochemistry(IHC) was used to detect the growth of new born neurons in SGZ. Thioflavin S staining was used to detect the NFT and SP in the cerebral cortex of hippocampus in mice. 8-isoprostane and Aβ40,Aβ42 were detected by ELISA. Results   Compared with that of the normal group, the growth of new born neurons became slow and the formation of NFT and SP in the cerebral cortex of hippocampus increased in the pathological group. Compared with that of the placebo group, the growth of new born neurons became better and the formation of NFT and SP in the cerebral cortex of hippocampus decreased in the drug treatment group. The effect was more obvious in the female group than in the male group. 8-isoprostane and Aβ40, Aβ42 were down-regulated in AD mice obviously. Conclusion   The ethanol soluble extract of polygala can promote the growth of new born neurons in hippocampus and reduce the formation of NFT and SP in the cerebral cortex of hippocampus. It can also reduce OS and Aβ40, Aβ42, ameliorate the pathological defects in AD brain,and keep the function of normal neurons. Polygala may be one of the potential drugs to treat AD.

Key words: Alzheimer disease；Amyloid beta-protein；Neurons； Ethanol soluble extract of polygala； Oxidative stress