Protective Effects of an Acidic Polysaccharide of Panax ginseng on Hematopoietic and Immune Systems of Gamma-Rays-Irradiated Mice

An acidic polysaccharide of Panax ginseng (APG), so called ginsan, is known to have important immunomodulatory activities. It was recently reported that APG had radioprotective effects in mice but the detailed mechanism was not fully elucidated. We investigated the potential of APG to protect the hematopoietic and immune systems of mice from radiation injury by a single whole-body irradiation (WBI) in vivo. From our results, the counts of endogenous colony forming units (CFUs) increased in APGtreated mice, indicating that APG induced the regeneration of hematopoietic cells. In splenocytes, APG treatment decreased the percent of tail DNA, a parameter of DNA damage, and also accelerated the proliferation and recovery of splenocytes, compared with untreated, irradiated controls. Furthermore, the number of apoptotic cells was significantly decreased in splenocytes of APG-treated mice compared with that of irradiated controls. Overall, this study shows that APG can enhance the regeneration of hematopoietic stem cells, and promote the repair of damaged cells or the proliferation of the immune cells. Therefore, our current data provide evidence that APG can have radioprotective effects on hematopoietic and immune systems in vivo.