Toxicity of methimazole on femoral bone in suckling rats: alleviation by selenium

Selenium has a pharmacological properties and it is well considered as an antioxidant. The present study investigated the potential ability of selenium, used as a nutritional supplement, to alleviate bone impairments in suckling rats whose mothers were treated with methimazole, an antithyroid drug.

Female Wistar rats were randomly divided into four groups of six each: group I served as control which received standard diet; group II were rendered hypothyroid by administration of methimazole (250 mg L(-1) in their drinking water); group III received both methimazole (250 mg L(-1) in their drinking water) and selenium (0.5 mg kg(-1) of diet); group IV received 0.5 Na(2)SeO(3) mg kg(-1) of diet. Treatments were started from the 14th day of pregnancy until day 14 after delivery.

Methimazole treatment decreased femur length and weight in 14-day-old rats, when compared to controls. Femur antioxidant enzyme activities, superoxide dismutase, catalase and glutathione peroxidase decreased. Lipid peroxidation recorded an increase revealed by high femur malondialdehyde levels. Methimazole also caused a significant decrease in calcium and phosphorus levels in bone. Yet, in plasma and urine, they increased and decreased inversely. Besides, plasma total tartrate-resistant acid phosphatase was enhanced, while total alkaline phosphatase was reduced. Co-administration of selenium through diet improved the biochemical parameters cited above. Nevertheless, distorted histoarchitecture revealed in hypothyroid rat femur was alleviated by Se treatment.

The present study suggests that selenium is an important protective element that may be used as a dietary supplement protecting against bone impairments.