Immunomodulation by Stemona tuberosa ethanol extract in vitro and in ovalbumin-induced mouse asthma model

In the present study, we investigated the immunoregulatory effects of Stemona tuberose (ST) in an in vitro and in ovalbumin (OVA)-induced asthma model. Murine spleen cells were isolated from normal and OVA-treated mice and the cytokine levels from T-cells in supernatants were determined by enzymelinked immunosorbent assay (ELISA). The results of the in vitro experiments indicated that ST modulated the balance between Th1 and Th2 cytokines. In addition, in the in vivo experiments we showed that ST significantly increased the levels of interleukin-2 (IL-2) and interferon-γ (IFN-γ) and decreased those of IL-4, IL-5 and IL-13, as compared with OVA control. Reverse transcriptionpolymerase chain reaction (RT-PCR) was carried out to determine the GATA-3/T-bet ratio. Results showed that ST modulated the Th2/Th1 imbalance by inhibiting GATA-3 and enhancing T-bet. The hematoxylin and eosin (H&E) stain studies on lung tissues indicated that ST had potential inhibitory ability on inflammation cells. Taken together, these findings suggest that the ethanol extract of ST might have compounds with immunomodulation potential.