الملخص

Background: The appropriate function of the ovary depends on the proper function of other endocrine glands especially the thyroid gland, which is the largest endocrine glands in the body. Hypothyroidism is a common thyroid disorder which commonly affect females and influence the function of reproductive system. Aim of this study : This work is to focus on the structural changes in ovary of adult female rats induced by hypothyroidism and the role of selenium. Methods: Thirty adult female rats were used. They were classify into 3 groups (10 animals in each group): Group I ( control) taken 0.5 ml distilled water orally for 3 months . Group II ( hypothyroid ) they were given antithyroid drug, carbimazole in a dose of 6 mg/ kg orally by gastric tube for 3 months. Group III (hypothyroid + selenium ) this group were treated by carbimazole as same as group II then added selenium in the last 2month in a dose of 10 µg/ kg orally. At the end of experiment , blood samples were taken for assessment of serum TSH ,T4 , FSH, LH, and estradiol, then animals were sacrificed and the ovaries were fixed in 10% formalin solution and prepared to be examined under the light microscope. Results: Serum concentration of TSH was significantly increase while the level of T4, LH, FSH, and estradiol concentrations were significantly decreased in both treated groups. The ovaries of hypothyroid groups showed degenerative changes of most growing follicles. Many atretic follicles and corpus luteum were observed with increase of collagen fibers and edema in the stroma associted with congestion of blood vessels. Treating of hypothyroid rats with selenium for two months produced an improvement in hormonal level and histological structure of the ovarian tissue. Conclusion: Hypothyroidism affect the structure of ovarian tissues but adding selenium has ameliorative role on thyroid function and histological changes of ovary which may be attributed to its antioxidant activity.