Antithyroid drug or hypothyroidism causes cellular damage inthe renal cortex of adult male albino rats: a histological andimmunohistochemical study

IntroductionThyroid and kidney functions interact with each other in the respective organ’sdiseased states. Drugs used to treat the respective diseases may have adverseeffects on the other organ’s functions. Antithyroid drugs cause hypothyroidism aswell as renal dysfunction through immune mechanisms. The extrathyroidal effects ofantithyroid drugs could contribute to oxidative stress and nitrosative stress and tocellular damage in the kidney.AimThis study aimed to determine whether antithyroid drugs (e.g. methimazole) orhypothyroidism itself causes cellular damage in the rat renal cortex.Materials and methodsTwenty-five male albino rats were randomly divided into four groups. Group I(the control group) was subdivided into the euthyroid group and the falsethyroidectomy group. Group II included rats with thyroidectomy-causedhypothyroidism. Group III included rats with methimazole-induced hypothyroidism,which received 60 mg/kg/day of methimazole in drinking water. Rats in group IVreceived methimazole (60 mg/kg/day) and l-thyroxine (T4) injection (20 μg/kg/day, subcutaneous). At the end of treatment (4 weeks for the pharmacologicalgroups and 8 weeks for the surgical groups), the animals were anesthetized andsamples of kidney and sera were obtained. Renal cortex changes were evaluated bybiochemical, histological, and immunohistochemical study.ResultsThe histological study revealed that only the methimazole-treated group showedcellular damage in the renal cortex. This damage was associated with an increasein oxidative and nitrosative stress, which was not compensated for by the decreasein the renal antioxidant enzymes and led to H2O2-caused cellular damage. The renalcortex in thyroidectomized rats did not show any histological alteration. Animalstreated with methimazole with a T4 supplement showed less damage in the renalcortex.ConclusionMethimazole induces hypothyroidism and causes cellular damage in the renalcortex, and these effects are not caused only by hypothyroidism induced by surgicalthyroidectomy. l-Thyroxine (T4) can improve the renal cortex changes.