α-Lipoic Acid Ameliorates The Changes in Prooxidant-Antioxidant Balance in Liver and Brain Tissues of Propylthiouracil-Induced Hypothyroid Rats

There are controversial data about the prooxidant-antioxidant balance in hypothyroidism. We aimed to investigate the effect of α-lipoic acid (ALA) on oxidative stress parameters in the liver and brain of propylthiouracil (PTU)-induced hypothyroid rats. In this experimental study, PTU (500 mg/L) was given to rats in drinking water for 10 weeks. ALA (0.2% in diet) alone and together with thyroxine (T4, 20 μg/kg body weight, s.c) were given to hypothyroid rats in the last 5 weeks of the experimental period. The levels of reactive oxygen species, malondialdehyde, protein carbonyl, ferric reducing antioxidant power (FRAP) and glutathione (GSH) levels, superoxide dismutase, and GSH peroxidase activities were determined in the liver and brain of rats. Histopathological examinations were also performed. Prooxidant parameters were increased in the brain but not liver in hypothyroid rats. ALA treatment alone lowered enhanced brain oxidative stress in hypothyroid rats. Also, ALA was found to ameliorate the changes as a result of oxidative stress arising from T4 replacement therapy. Our results indicate that ALA alone and together with T4 may be useful in reducing oxidative stress in thyroid dysfunctions.