Betaine as a methyl donor and an antioxidant agent in levodopa-induced hyperhomocysteinemia and oxidative stress in rat's kidney

Betaine has been shown to be antioxidant and methyl donor effects in our recent studies. In the present study, the antioxidant and methyl donor properties of betaine in levodopa/benserazide-mediated hyperhomocysteinemia and levodopa-induced oxidative stress in rat's kidney were examined. Sprague-Dawley male rats were divided into levodopa (LD), Betaine (Bet.), levodopa plus betaine (LD/Bet.), levodopa plus benserazide (LD/Ben.), levodopa plus betaine-benserazide (LD/Bet.-Ben.), and control groups. The experimental groups received LD (3 × 100 mg/kg), Bet. (1.5% w/w of the total diet), Ben. (3 × 25 mg/kg), and distilled water was given to controls for 10 consecutive days, orally by gavage. Plasma total homocysteine (tHcy) concentration decreased significantly in Bet.-, LD/Bet.-, and LD/Bet.-Ben.- treated rats compared to LD/Ben. group. Thiobarbituric acid reactive substances concentration (as a lipid peroxidation marker) in renal tissue reduced statistically in betaine group in comparison with LD and LD/Ben. groups. Renal catalase activity increased significantly in LD-treated rats when compared to controls. Renal superoxide dismutase activity significantly decreased in LD-treated group when compared to LD/Ben. group. However, there was not any significant difference in renal glutathione peroxidase (GPx) activity among the groups. These findings indicate that LD and LD/Ben. have side effects in kidney due to induction of hyperhomocysteinemia and oxidative stress. In contrast, betaine acts as a promising antioxidant and methyl donor agent versus LD-induced complications.