The effect of silymarin and gamma radiation on nucleic acids in rat organs.

The influence of silymarin on radiation-induced changes in concentrations of RNA and DNA was followed in male Wistar rats. The liver, spleen and bone marrow were examined at 30 h, 7, 14 and 21 days after 6 Gy whole-body gamma irradiation or 30 h and 7 days after 3 Gy whole-body gamma irradiation. Following silymarin treatment, a mild increase in the concentration and total content of RNA and DNA in liver and bone marrow at days 7 and 14 after administration was found; in spleen, total content of DNA significantly increased at 30 h. Silymarin administered 1 h before irradiation, moderated radiation-induced changes in nucleic acids in its target organ, liver, and in spleen and bone marrow. We suggest that beneficial effects of silymarin on radiation injury to the membranes of liver cells resulted primarily from its antioxidative ability and its ability to act as a radical scavenger, thereby preventing membrane permeability changes.