| Summary: | 碩士 === 國立臺灣大學 === 微生物與生化學研究所 === 96 === The purpose of this study is to evaluate whether the yam may possess an immunomodulation effect on the inflammatory disease such as rheumatoid arthritis. First, the effect of ethyl acetate extract of Taiwanese Yam (Dioscorea altata L. cv. Tainung No.2) (DAEA) on in vitro cytokines secretion by RAW264.7 cell, primary macrophages or splenocytes from C57BL/6 mice was investigated. The results showed that DAEA significantly inhibited IL-6 secretion in LPS-stimulated RAW264.7 cell and IFN-γ secretion from ConA-stimulated splenocyte, and tended to decrease IL-6 secretion in LPS-stimulated primary macrophages, suggesting an anti-inflammatory effect. Therefore, in vivo anti-inflammatory effect of DAEA on rheumatoid arthritis was evaluated using a collagen-induced arthritis (CIA) murine model. Female C57BL/6 mice were immunized with type II collagen (CII) emulsion with CFA containing 5 mg/mL of M. Tuberculosis subcutaneously. On day 21, mice were boosted with the same dose of CII and CFA, and then divided into four groups by titer of CII-specific IgG2a, body weight and the swelling of joints (toal score). Four groups of mice were fed chow diet (control and PBS), tube-feeding of 100 (DAEA-L) or 200 μg (DAEA-H) EA extracts of yam per day. After 17 days feeding, the total score of DAEA-H group tended to decrease compared to the control group. Then, mice were sacrificed for further in vivo analysis. Compared to the control group, DAEA-H significantly increased IFN-γ secretion under ConA or LPS-stimulated splenocytes. To obtain better induction of arthritis in murine model, second in vivo experiment was conducted by using a type II collagen antibody-induced arthritis (CAIA) model. Female BABL/c mice were immunized with type II collagen antobody and then divided into five groups by weight and score. Five groups of mice were either fed an AIN-76 diet (control and PBS), AIN-76 diet containing 0.9% cooked yam (DA-cook), tube-feeding of 100 (DAEA-L) or 200 μg (DAEA-H) EA extracts of yam per day. After 11 days’ feeding, the total score of DA-cook and DAEA-H group was significantly lower than that of the control group. Total score of the DAEA-L group tended to be lower than the control group. Mice were sacrificed for further in vivo analysis. The results showed that DAEA-L significantly inhibited TNF-α、IL-6 and IL-1β secretion in LPS-stimulated splenocytes. DAEA-L decreased IFN-γ secretion by ConA-stimulated splenocytes and IL-12p40 on CII-stimulated splenocytes. Furthermore, histology also showed the group of DAEA-L and DAEA-H had eased immune cells recruitment and bone erosion. In conclusion, these results suggest that the EA extract of yam, Dioscorea alata L. cv. Tainung No.2 used in this study, may alleviate arthritis trough suppression of Th1 cytokines and pro-inflammatory mediators, which may be beneficial for rheumatoid arthritis.
|
|---|
