الفهرس 
Introduction and aim of the workOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
Dinbutyl Phthalate (DBP) is one of the most pollutant widely used as plasticizer, adhesives, plastic coatings and cosmetic formulations. They occur in some foods (milk, cheese, meat, fish and eggs) as well as affected the environmental compartments such as in water, air, and sediments. It is well known that some phthalates are reproductive toxicants, although the mechanism of this toxicity is not yet clear. The aim of the present study was to clarify the hazardous effects of this phthalate compound on the development of the testis, the ovary and the thyroid gland during postnatal life. Coadministration of phthalate and propylthiouracil (PTU) to induce hypothyroidism was involved in separate groups to examine the possibility that phthalate asters induce their effects on gonads by interfering with the hypothyroidism. Besides, the adverse effects of phthalate alone or in combination with propylthiouracil on the induction congenital abnormalities and development of ossification of axial and appendicular regions in newly born young were also investigated. 1. Material and Methods: Sixty pregnant albino rats weighing approximately (100120 gm) were used. They were arranged into the following groups: control groups, dinbutyl phthalate (DBP)treated group (50mg/100g), propylthiouracil (PTU)treated group (5mg/100g), and combined phthalatepropylthiouraciltreated group. Each individual of the different treated groups has received daily oral doses of DBP, propylthiouracil, or a combination of both from the 8th to the 16th day of pregnancy. The offspring of both control and the experimental groups at oneday as well as 1,3,5,7 and 9 weeksage were investigated. The testis, ovary and thyroid gland were separated and processed for histological investigation by staining with haematoxylin and eosin. In case of newly born youngs, the gross morphology, body weight, crownrump length and ossification of axial and appendicular skeleton were studied. 2. Results: The results summarized as follows: 1. The newly born and postnatal youngs maternally treated with phthalate alone or in combination with propylthiouracil exhibited a slowing growth rate comparing with the control. The mean crownrump length and body showed a slight reduction in comparison with the control. The ossification of the skeleton was markedly delayed These changes could be attributed to the transplacental passage of DBP and its metabolites to the embryonic tissues interfering with cell growth and differentiation. 2. The testis of newly born and postnatal youngs aging 1,3,7, and 9 weeks revealed a delay in maturation associated with the reduction in the diameter of seminiferous tubules, increased degeneration and arresting maturation of germ and Sertoli cells. The seminiferous tubules exhibited numerical reduction of spermatogenic cell. Many of the germ cells appeared either swollen or degenerated. Postnatal young rats maternallytreated with phthalate alone or in combination with propylthiouracil showed the highest hazardous effects. 3. The ovary shows a dramatic effects manifested by in interruption of folliculogenesis and luteinization. These ovarian lesions involved atresia in differentsized ovarian follicles, pyknosis and degeneration of granulosa cells, and hypercellularity of stromal tissue. These estrogenslike alterations may be explained by the reduced synthesis of estrogen induced by phthalate resulting in degeneration of granulosa cells. 4. The thyroid gland of newly born and postnatal youngs maternally treated with phthalate alone or in combination with propylthiouracil exhibited massive atrophy and degeneration of thyroid follicles. The epithelial cells lining the follicles appeared necrotic. These effects could be attributed to the effect of phthalate on the hypothalamicpituitarythyroid axis. The present work concluded that PTU administration concomitantly with DBP to pregnant rats increased the incidence of testicular, ovarian and thyroidal lesions, as well as developmental toxicity in their offspring. A great attention should be directed to women with hypothyroidism that are exposed to the toxic effects of such phthalate plasticizer.