Induction of secretory and tumoricidal activities in peritoneal macrophages by ginsan

Abstract

The immunomodulatory effect of ginsan based on the production of cytokines and the activation of macrophage was studied. Murine peritoneal macrophages (PM) on in vitro treatment with ginsan isolated from Panax ginseng induced mRNA of cytokines such as tumor necrosis factor (TNF)-α, interleukin-1 (IL-1)β, interleukin-6 (IL-6) and interleukin-12 (IL-12); TNF-α mRNA induction was maximum within 3 h, IL-6 mRNA was gradually induced up to 24 h, and IL-1β and IL-12 mRNA were highly induced at 24 h. IL-1β and IL-6 protein levels also increased within 24 h in a dose-dependent manner and reached a maximum with 100 μg/ml ginsan. IL-12 was induced after 3 days and a high level of induction was detected after 4 days post treatment. Ginsan enhanced the lytic death of L929 cells through TNF-α activation. The mRNA expression of nitric oxide synthase (iNOS) was highly induced after 24 h treatment of ginsan, and then NO production was maximum after 48-h treatment with a low dose of 1 μg/ml. The level of iNOS mRNA induction by ginsan was slightly less than that of macrophages activating agents such as LPS plus IFN-γ. The tumoricidal activity of macrophage cultured with ginsan on Yac-1 cells was enhanced in a dose-dependent manner; growth inhibition increased 1.6-fold with 100 μg/ml ginsan. These results suggest that ginsan exerts as an effective immunomodulator and enhances antitumor activity of macrophages.