Diosgenin, a steroidal sapogenin, enhances antigen-specific IgG2a and interferon-γ expression in ovalbumin-sensitized BALB/c mice
Date Issued
2006
Date
2006
Author(s)
Kuan, Chio-Chin
DOI
en-US
Abstract
Chinese yam is a commonly used herb in Taiwan and several other Asian countries. The most abundant steroidal sapogenin contained in the root of Chinese yam is diosgenin (DIO), which has been shown to exhibit a number of biological activities. The objective of the present study was to investigate the effect of DIO on antibody production and T-cell reactivity in BALB/c mice sensitized with ovalbumin (OVA) and subsequently challenged with aerosolized OVA. Mice were administered with DIO (200 or 400 mg/kg) by gavage daily for 34 days. Serum samples were obtained 2 weeks after each OVA sensitization, and mice were sacrificed 2 days post the OVA challenge. Diosgenin treatment attenuated the production of OVA-specific IgE and total IgE in serum obtained after the 1st Ova sensitization, but significantly enhanced IgG2a in serum after the 2nd sensitization. In parallel with the enhancement of anti-OVA IgG2a, the expression of the Th1 cytokine IFN-gamma and T-bet transcription factor in splenocyes isolated from DIO-treated mice was markedly elevated, whereas the expression of the Th2 cytokine IL-4 and GATA-3 transcription factor was unaffected. Accordantly, DIO treatment did not affect the steady state mRNA expression of IL-4 in the lungs of mice sensitized and challenged with OVA. Moreover, the production of mucin and infiltration of inflammatory cells in the lungs of OVA-sensitized and challenged mice were not affected by DIO treatment. Taken together, the data suggest that exposure of mice to DIO results in modulation of the immune response toward Th1 direction in response to OVA sensitization, whereas Th2 cell-derived immunity and allergic airway reactions were relatively unaltered. The present study is the first report to show the immunomodulatory activity of DIO in vivo. Our data provide the evidence that intake of DIO, the major sapogenin contained in Chinese yam, may up-regulate certain aspects of immunity due to the enhancement of IFN-gamma expression and Th1 differentiation.
Subjects
山藥
植物固醇
免疫調節
T細胞
細胞激素
基因表現
Chinese yam
diosgenin
steroidal sapogenin
T cell
cytokine
gene expression
Type
thesis
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