| Summary: | 碩士 === 中原大學 === 生物科技研究所 === 104 === Aging is an important risk factor for the pathogenesis of neurodegenerative diseases. Therefore, the treatment and prevention of neurodegenerative diseases are one of the most important public health problems. Diosgenin (3β-hydroxy-5-spirostene), a naturally occurring steroid saponin found abundantly in yams. Previous reports have been indicated that diosgenin possess the function of neuroprotection. Herein, we want to investigate the neuroprotective effects of diosgenin on aging rats (19 months old). We compared the behavior of aging rats fed diets with or without 0.1 wt% diosgenin for 8 weeks. The results indicated that spatial learning and memory ability of aging rats fed with diet containing diosgenin is better than control group in Morris water maze test. Compared to control, diet containing diosgenin could induced aging rats preferred to explore a new arm compared with conteol group in Y-shaped maze test. In addition, diosgenin-induced down-regulation of the expression of IL-1β, whereas the epression of TNF-α and iNOS was not changed in the hippocampus of aging rats by RT-QPCR. Additionally, diosgenin-treatment induced significantly reduction of phosphorylation of tau and increased the expression of the presynaptic proteins synaptophysin and postsynaptic PSD95 in the hippocampus of aging rats by Western blot analysis. Furthermore, by evaluating the immunohistochemical results of iba1 staining showed that diosgenin attenuated microgial activation; however, Ki67 staining indicated that the cell proliferation was not affected. These results suggest that diosgenin ameliorate age dependent cognitive deficits which may be partly mediated via suppression of activated microgial and preventing synaptic dysfunction.
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