Assessment of the Protective Effects of Selenium and Zinc against Potassium Dichromate Induced Thyrotoxicity in Preimplanted <i>Wistar albinos</i> Rats

Abstract

Hexavalent chromium is an environmental pollutant considered to be an endocrine-disrupting metal. Selenium and zinc are essential trace elements, known to play a crucial role in thyroid homeostasis. The purpose of the current work is to investigate the effects of potassium dichromate (K₂Cr₂O7) administrated subcutaneously (s.c) on the 3rd day of pregnancy in preimplanted rats by using graded doses (10, 50, 100 mg/kg, s.c) or K₂Cr₂O7 (10 mg/kg, s.c) in association with Selenium (0.3 mg/kg, s.c) and Zinc chloride (20 mg/kg, s.c). The hormonal profile, apoptosis induction and histological changes in thyroids were evaluated. Our main findings showed that K₂Cr₂O7 promoted hypothyroidism with a significant decrease in plasma T3 and T4 levels (P<0.001), while plasma TSH level increased significantly (P<0.001), in addition, a hypertrophy of the thyroid was noted (P<0.01). Moreover, K2Cr2O7 (10 mg/kg, s.c) induced apoptosis via the caspase 3 pathway (P<0.001) and altered the gland histoarchitecture. The co-treatment with Se or ZnCl₂ has ameliorated the hormonal status and restored partially the thyroid histoarchitecture. We concluded that the administration of Selenium and Zinc can prevent the hazardous effects of potassium dichromate on the hormonal and histological status of the thyroid gland in preimplanted Wistar albino rats.