Immunomodulatory Effects of Cinobufagin on Murine Lymphocytes and Macrophages

Cinobufagin (CBG), a major bioactive component of the traditional Chinese medicine ChanSu, has been reported to have potent pharmacological activity. In this study, we aimed to elucidate the effects of CBG on the activity of immune cells in mice. Peritoneal macrophages and splenocytes from mice were prepared and cultured in RPMI1640 supplemented with 10% fetal bovine serum. Concanavalin (ConA), lipopolysaccharide (LPS), and CBG (0.0125, 0.05, 0.15, or 0.25 μg/mL) were added to the culture medium, and the phagocytic activity of macrophages was detected by MTT assays. Additionally, lymphocyte secretion of interleukin- (IL-)2 and IL-10 was detected by enzyme-linked immunosorbent assay, and the cell cycle distribution and cell surface markers were detected by flow cytometry. Our results demonstrated that CBG promoted lymphocyte proliferation; this effect was suppressed by combined treatment with ConA or LPS. Moreover, CBG also significantly improved the CD4(+)/CD8(+) ratio in spleen lymphocytes and increased the percentage of spleen lymphocytes in the S phase. Finally, we found that CBG enhanced the secretion of IL-2 and IL-10 and increased the phagocytosis ability of macrophages. In summary, CBG could enhance activity of immune cells.