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DOI: 10.1055/s-2007-967169
© Georg Thieme Verlag KG Stuttgart · New York
Diosgenin, a Steroidal Sapogenin, Enhances Antigen-Specific IgG2a and Interferon-γ Expression in Ovalbumin-Sensitized BALB/c Mice
Publication History
Received: September 12, 2006
Revised: January 24, 2007
Accepted: February 26, 2007
Publication Date:
04 April 2007 (online)


Abstract
The effect of diosgenin, the most abundant sapogenin in Chinese yam, on humoral immunity was investigated. Ovalbumin (OVA)-sensitized and challenged BALB/c mice were administered daily with diosgenin for 34 days. The production of OVA-specific serum IgG2a was significantly enhanced by diosgenin treatment, whereas total IgE and OVA-specific IgG1, IgG2a and IgM were unaffected. In parallel with the enhancement of IgG2a, OVA-induced IFN-γ secretion and mRNA expression were markedly elevated in splenocytes of diosgenin-treated mice, whereas IL-4 expression was unaltered. Furthermore, the expression of T-bet, but not of GATA-3, in splenocytes was up-regulated by diosgenin administration. However, diosgenin treatment did not modulate IL-4 mRNA expression and inflammatory cell infiltration in the lung of OVA-sensitized and challenged mice. Collectively, these data suggest that diosgenin regulates the systemic immune response towards the Th1 direction in response to OVA sensitization. The present study provides evidence to show that intake of diosgenin modulates certain aspects of acquired immunity, including the enhancement of antigen-specific IgG2a and IFN-γ expression, which may be mediated through the up-regulation of Th1 differentiation.
Abbreviations
BW:body weight
DIO:diosgenin
ELISA:Enzyme-linked immunosorbent assay
GAPDH:glyceraldehyde-3-phosphate dehydrogenase
Ig:immunoglobulin
IL:interleukin
NA:naïve
O.D.:optical density
OVA:ovalbumin
RT-PCR:Reverse transcription-polymerase chain reaction
S.E.M.:standard error of mean
Th:T helper
TNF:tumor necrosis factor
VH:vehicle
YMP:yam mucopolysaccharide
Key words
Diosgenin - antibody - ovalbumin - interferon-γ - T-bet
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