Journal of Rawalpindi Medical College (Mar 2015)
Effect of Experimentally Induced Hypothyroidism and its Treatment by Thyroxine on the Number of Follicles in an Ovary of Wistar Rats.
Abstract
Background: To observe the effects of hypothyroidism on histological structure of ovaries and also to evaluate the effect of treatment of hypothyroidism on the morphological structure of ovary. Methods: In this experimental study forty five Wistar Albino rats were monitored for 10 days to rule out any diseased or medically unfit animals by keeping them in an experimental room. They were kept on balanced diet ad-libitum and normal tap water. The constant weight gain by an animal was taken as a healthy parameter. Forty five animals were divided into 3 groups, comprising of fifteen animals in each group. The control group only received tap water and normal balance diet. The hypothyroid group received carbimazole at a dose of 0.02% per ml in normal drinking water through feeding tube for six weeks. The thyroxine treated group initially received carbimazole at a similar dose for four weeks and then received intra-peritoneal injections of thyroxine at a dose of 5μg daily as a single dose for following two weeks. All the animals were sacrificed at the end of six weeks by deep ether anesthesia. Both ovaries of rats were isolated, fixed in Bouin’s fixative overnight and about 5μm thick sections were prepared and stained with hematoxylin and eosin (H&E) for assessing the follicular development. Results: The total number of follicles was markedly reduced in hypothyroid group on both the right and left sides and an improvement in the number of follicles were observed in the thyroxine treated group. There was no significant difference in the size and number of follicles between the two sides of an animal. Conclusion: Hypothyroidism produces significant changes in the morphology of ovarian structure. This change in the morphology can revert back to approximately normal by treatment with thyroxine
