Role of Montelukast in Alleviation of Toxicity Induced by Cadmium in Thyroid Gland of Adult Male Albino Rats. (Histological, Immunohistochemical and Biochemical Study)

Background: Cadmium is a common toxic heavy metal of great concern for environmental pollution and human health. It is extensively used in many industries as radiation screens, rechargeable batteries and pigments. Montelukast is a powerful highly effective anti-inflammatory drug. Recently it shows significant antioxidant properties.Aim of the Study: evaluate the effect of Cadmium on thyroid glands and to assess the possible protective role of MontelukastMaterials and Methods: Forty adult male albino rats were divided into four equal groups received treatment for 6 weeks: (I) (Control group) received distilled water. (II) (Cadmium group)"3mg/kg". (III) (Recovery group) kept untreated for another 6 weeks after Cadmium administration with the same dose and period as pervious group. (IV) (Montelukast and Cadmium group) received Montelukast "10mg/kg" and Cadmium"3mg/kg". At the end, all animals were sacrificed. Thyroid gland samples were obtained for histological and immunohistochemical studies. Blood samples were obtained for hormonal assay. Data was statistically analyzed.Results: Histological examination of thyroid glands of Cadmium treated rat’s showed disorganization and irregularity in the follicles. The follicular cells appeared distorted with pyknotic nuclei and some cell desquamated in follicular lumen. Colloid retraction within the follicles, cellular infiltration around congested blood vessels and marked collagen fibers deposition in connective tissue septae were detected. Significant increase in Caspase-3 immune expression in the follicular cell’s cytoplasm was noticed. High significant decrease of thyroid hormone (T3, T4) level was noticed. These changes were still seen in the recovery group. Co-administration of Montelukast showed obvious protection against the hazardous effects of Cadmium. Conclusion: Cadmium induces marked thyroid tissue damage via, fibrosis and apoptosis. These structural changes can be alleviated by combined treatment with Montelukast.