Protective effects of gomisin A isolated from Schisandra chinensis against CCl4-induced hepatic and renal injury

The aim of the present study was to investigate the protective effects of gomisin A, a lignan compound isolated from Schisandra chinensis, against liver and kidney damage induced by CCl4 exposure. We assessed alterations in organ weights, levels of serum biochemical indicators, and activation of the caspase-3 and MAPK signaling pathways and carried out histological analysis of liver and kidney tissue in rats pretreated with gomisin A for four days. In the gomisin A/CCl4-treated group, only the liver experienced a significant increase in weight, whereas the other organs did not undergo any changes. Five biochemical indicators in serum indicated that liver and kidney toxicity dramatically decreased upon gomisin A pretreatment, although the decrease in ratios varied. Upon histological analysis, the gomisin A/CCl4-treated group showed less hepatocellular necrosis, a poorly dilated central vein in the liver section, decreased diameter of the glomerulus, a lower number of capillaries, and a convoluted tubule in the kidney section. Furthermore, the formation of active caspase-3 was inhibited by gomisin A pretreatment in the gomisin A/CCl4-treated group, whereas the expression level of Bax protein was slightly increased. Western blot analysis revealed that there were differences between the liver and kidney in terms of activation of the MAPK signaling pathway. In the liver, gomisin A pretreatment increased phosphorylation of three members of the MAPK pathway when compared to that in the vehicle pretreatment group. However, in the kidney, only the phosphorylation level of p38 was elevated upon gomisin A pretreatment, whereas levels of the other two members were decreased. These results suggest that gomisin A induces marked protective effects against hepatic and renal injury induced by CCl4 exposure through differential regulation of the MAPK signal transduction pathway.