دراسة دور هرمون Dehydroepiandrosterone DHEA في الفعاليات التكاثرية والنسجية في اناث الارانب المحلية Oryctolagus cuniculs المستحدث بها قصور الدرقية‎ جراحياً ‏وعلاجياً

Study the role of Dehydroepiandrosterone (DHEA) hormone in Reproductive efficacy and histological effects in local female rabbit Oryctolagus cuniculus which induced of hypothyroidism surgically and therapeutically

This study was designed to investigate the effect of the steroid hormone (DHEA) on the physiological and histological Changes caused by induced hypothyroidism (surgically and by Carbamizol) in adult female rabbits. The study also investigated the effect of hypothyroidism on reproductive efficiency in females rabbit: the percent study included two experiments.

The first experiment induction of partial Thyroidectomy. In the first experiment, 25 female adult rabbits were randomly divided into five equal groups (five animals / group). The first group included animals with partial thyroidectomy only (G1). The second group was included animal with partial thyroidectomy and drenched with DHEA hormone (2 mg / kg) for 4 weak (G2). The Third group was administered water was considered as a positive control group (G3) and the fourth group (G4) animal were administrated only of (2 mg / Kg) DHEA. Finally animals of fifth group (G5) were with Shame opperation, which performed by surgical operation of the skin and muscle only without partial thyroidectomy considered as a negative control group. Blood samples were collected at the end of the experiment and the following criteria were studied: Thyroxin concentration (T4) concentration of triiodothyronine (T3), Follicle-stimulating hormone (FSH) concentration, estrogen concentration (E2), Luteinizing hormone (LH) concentration The concentration of DHEA –S hormone, as well as the study of the immunohistochemical expression of the thyroid hormone protein Thyroglobulin (TG) in thyroid gland and the estrogen receptor-Alpha (ERα) in pituitary gland as well as taking the histological sections of the thyroid, adrenal, pituitary, uterine, ovary and liver tissue.

The results showed a significant increase in the level of TSH in the partial surgical excision groups (Thyroidectomy) accompanied by a significant decrease in the concentration of T4, T3 hormone in the partial Thyroidectomy group compared with negative and positive control group and the treatment group with hormone and showed a significant increase in the level of T4 hormone in the Thyroidectomy with DHEA hormone group compared with the Thyroidectomy group and positive , negative control group . and significant increase in the level of hormone E2 and DHEA-S and LH and FSH in the groups of treatment with hormone DHEA compared with the negative and positive control group and the group of surgical excision only. While the results of the histology showed clear changes of thyroid gland Increased thyroid follicles. and hyperplasia or hyperplastic cell in the thyroid follicles cells . Degenerative changes of the adrenal and pituitary cells and congestion of blood vessels. As well as decrease in the number of ovarian follicles in the ovary and vacuolated degenerative change in the cells of the mucous layer of the uterus and the precence of fatty droplets and inflammatory cell infiltration around the central vein of the liver tissue in the partial Thyroidectomy. While no changes were observed in the DHEA treatment groups.

The results of the IHC technique for thyroglobulin in thyroid tissue showed a significant increase in the histologic immunoglobulin expression (strong expression) in the partial Thyroidectomy group compared to the other groups. and significant increase expression of the estrogen receptor in the pituitary gland in the DHEA group compared to the other group.

The second experiment using Carbamizol to induced hypothyroidism. Twenty adult female rabbits were used and divided into four equal groups (5 animal / group): Group 1 animals (G1), which were administered 0.02 mg / kg Carbamizol for four weeks . The animals of the second group (G2) was orally drenched with water was considered as a control group. G3 animals were with 2 mg / kg DHEA and 0.02 mg / kg with Carbamizol oral administration. The fourth group (G4) was given DHEA only. Blood samples were collected at the end of the experiment to measure all the hormonal criteria above in the first experiment. The histological sections of the thyroid gland, adrenal, adrenal, uterine, ovary and liver were also taken. The thyroid thyroglobulin was measured for the thyroid gland and the estrogen receptor in the pituitary gland. The results showed a similar pattern to the results of the first experiment of the hormonal changes include an increase of TSH and lower in thyroid hormone hormone T4, T3 in the group that was drug Carbamizole compared to the control group and the rest of the groups did not differ significantly between them and also a significant increase in the level of hormone DHEA-S in groups of hormone treatment compared to Control group and Carbamizole –induced hypothyroidism group, as well as a significant increase in estrogen concentration in the DHEA groups compared to the control group and the Carbamizol-induced hypothyroidism group. The concentration of FSH was significantly different in the DHEA group compared with the rest of the hormone Which did not differ significantly between them. There was also a significant increase in levels of the LH hormone in the groups treated with DHEA compared to control group. The histological results showed presence the necrosis and degeneration in the follicular cells and the presence of vacuoles and hypertrophy of the thyroid follicular cells , and degenerative changes in the pituitary gland and the adrenal gland, as well as degenerative changes in the uterus tissue, reduced ovarian follicles and inflammation of inflammatory cells in liver tissue in the Carbamizole treatment group compared to groups that were drenched with DHEA hormone. The results of histochemical immunoglobulin did not show a high expression of TG in the groups of the Carbamizol induced hypothyroidism compared to the first experiment. significant increase in histochemical expression of the estrogen receptor in the DHEA groups compared to the other groups

Conclusions

The results of the present study indicate that the dosage of 2 mg / kg DHEA was safe and did not cause any changes in the tissues of the organs or hormonal changes, on the other hand, this hormone ameliorates the harmful effects of hypothyroidism .