Protective effects of l-carnitine and alpha-lipoic acid in rats with adjuvant arthritis

Free radicals play an important role in the pathophysiology of adjuvant arthritis. The purpose of this study was to assess the efficacy of l-carnitine (LC) and alpha-lipoic acid (α-LA) which are known to have antioxidant effects, in the treatment of adjuvant arthritis.Arthritis model was created by the administration of complete Freund's adjuvant (CFA) in 32 of 40 male Sprague-Dawley rats. The rats were divided into five groups. Rats in Group I served as controls and received 0.1 ml kg−1 saline. Group II received only 0.1 ml of CFA and served as the CFA-control for the other groups. Groups III–V, after being injected with CFA, were treated with LC, α-LA or diclofenac, respectively. Levels of malondialdehyde (MDA) and glutathione (GSH) were measured in plasma samples. Enzyme activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were measured. The paws of rats were evaluated histopathologically to investigate the anti-inflammatory effects. TNF-α levels were measured for the evaluation of inflammation. In Group II plasma MDA increased, levels of glutathione decreased, enzyme activities of SOD and GPx decreased. Histopathological damage increased in the paws of the rats in this group. MDA levels decreased in Groups III–V when compared with Group II. GSH levels significantly increased in Group III and IV than Group V. SOD activity of Group IV was higher than Group III and V. TNF-α levels were significantly lower in Group IV and V.LC and α-LA seemed to have protective effects against oxidative damage in adjuvant arthritis model.