Protective role of lipoic acid on methotrexate induced intestinal damage in rabbit model

Methotrexate (MTX), a folate antagonist agent, is mainly used in treatment of malignant tumors and auto immune diseases and affects not only tumor cells, but also gastrointestinal mucosa. The present study was undertaken to determine whether lipoic acid (LA) could ameliorate methotrexate-induced oxidative intestine injury in rabbits. Twenty-one rabbits were randomly assigned into three groups: Group 1 (control group), Group 2 (received 20 mg/kg MTX), Group 3 (received MTX plus LA 75 mg/kg orally). On the 6th day rabbits were anesthetized and intestinal tissue sampled for pathologic and biochemical assessment. The intestinal tissue injury index and malondialdehyde (MDA) levels were lower in MTX+LA group as compared to the MTX group, and tissue glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity were higher in MTX+LA group than in the MTX group (p < 0.05). These findings suggest that co-administration of LA with MTX is associated with reduction in oxidative injury and tissue damage in the intestine. We suggest that lipoic acid may have a protective role in the MTX-induced oxidative injury.