Assessment of the Fertility Alterations in Adult Female Rats after Induction of Hyperthyroidism

Abstract

Abstract

To expand understanding the toxic effects of the hyperthyroidism at different stages on female reproduction, In this study, their roles on estrous cyclicity and mediators of inflammation, proliferation and apoptosis in rats‘ ovaries had been evaluated. To fulfill this purpose, mild, moderate, and severe hyperthyroidism were induced in adult female rats by daily oral administration of L-thyroxin for 10, 20, and 30 consecutive days, respectively. Any ovarian and uterine histological alterations were evaluated microscopically using hematoxylin and eosin stain. Serum levels of thyroid stimulating hormone (TSH), free triiodotyrosine (FT3), progesterone and estradiol II were assayed. The ovarian levels of interleukin-6 (IL-6) and insulin-like growth factor-1 (IGF-1) were investigated. The localization and expression of both proliferating cell nuclear antigen (PCNA) and B-cell lymphoma (BCl-2) were evaluated in ovaries by immunohistochemistry. The present study revealed a gradually significant elevation in serum FT3 with a gradually significant reduction in serum TSH. Mild hyperthyroidism did not alter serum level of estradiol II, while decreased significantly serum progesterone level, while moderate and severe hyperthyroidism decreased significantly their serum levels.