Effets de différentes doses de Dexaméthasone sur la fonction thyroïdienne chez le mouton Ouled Djellal

Abstract

Synthetic glucocorticosteroids are widely used in veterinary medicine for their antiinflammatory and immunosuppressive actions. However they are deemed to have multiple side effects such as hypothyroidism. The aim of this study was to define the effects of Dexamethasone (DEX) administered parenterally (IM) at therapeutic doses conventionally used in the anti-inflammatory and immunosuppressive treatments on the thyroid function in sheep. Fifteen sheep of Ouled Djellal breeds were randomly divided into three groups of five sheep each. The animals received an injection of Dexamethasone (DEXALONEND solution) at a rate of 1.52 mg DEX / J for 6 days for group1 and 3.4 mg DEX / J for 6 days for group 2, the third group has served as control group and did not receive any treatment. Blood samples taken over a period of 3 weeks were analyzed to define the plasma levels of free thyroid hormones fT4 fT3. It has been shown that Dexamethasone induced a significant decrease (P <0.05) of serum fT4 and fT3 24 hours following the start of treatment. Hormone levels have returned to their baseline values 24 hours after treatment withdrawal. From these results, we can deduce that Dexamethasone antithyroid-effects are transitory and therefore do not have a significant impact on the health of the animals.