[Studies on the mechanisms of immunoregulatory effects of ginsenoside Rg1 in aged rats].

Using methods of fluorescence flow cytometry and Western blot analysis, Rg1 was found to enhance the expression of IL-2 receptor alpha chain and inhibit the release of soluble IL-2 receptor. In in vitro experiment, Rg1 showed no influence on Con A-induced increase of cytoplasmic free calcium concentration, but significantly increased the levels of intracellular cAMP and cGMP in aged animals. In view of the important role of cAMP and cGMP as second messengers in the regulation of immune system, the results of the present studies suggest that one of the mechanisms by which Rg1 enhances immune function in old rats might be mediated by increase of cAMP and cGMP contents, resulting in IL-2 gene expression and splenocyte proliferation.