Effect of pyrethroids on female genital system. Review.

Pyrethroids have been associated with a range of toxicological effects on various organs in animals.Recent animal studies suggest that neurodevelopmental, reproductive, and immunological effects may result following exposure to some pyrethroids at levels below those that induce overt signs of neurotoxicity. A variety of pyrethroids and their metabolites have the potential to affect the reproductive system. Dose-dependent effects on reproduction are associated with exposure across pyrethroid types. In mammals, permethrin and tetramethrin and cypermethrin have been found to be associated with adverse effects at high doses. Fenvalerate, deltamethrin, cypermethrin, caused morphometric and structural changes in the female genital organs. These pyrethroids affect ovulation, cause atresia of follicles, decrease the number of follicular cells, oocytes and corpora lutea and induce vesicular atrophy of the endometrial glands. The potential hormonal activity of pyrethroids showed that certain pyrethroids and their metabolites have multiple effects on the endocrine system. The level of steroid hormones, such as progesterone and estradiol, was inhibited. The pyrethorids may have the potential to mimic estrogens or to inhibit estrogen action. Some metabolites of pyrethroids, in particular permethrin and cypermethrin, are more likely to interact with the cellular estrogen receptors than the parent pyrethroids. Though several pyrethroids posses low toxicity, some pyrethroids, such as deltamethrin, cypermethrin, fenvalerate and bifenthrin have showed considerable toxicity.

Changes in the peritubular tissue of rat testis after cadmium treatment.

The present study demonstrates histological and immunohistochemical changes in the peritubular testicular tissue of rat testis after application of cadmium chloride. After 5-day cadmium exposure, advanced deterioration of the boundary testicular tissue, mainly oedema, disarrangement of collagen fibres and peritubular cells, dilatation and thrombosis of blood vessels were observed. Changes in the boundary tissue were accompanied with desquamation of the germinal epithelium. Immunohistochemically, positive reaction for alpha-smooth muscle actin and desmin in tunica media of large testicular blood vessels basically was not affected. No reaction for vimentin was seen in endothelial cells of blood capillaries, whereas positive reaction presented only these cells in large blood vessels. The myofibroblasts positively reacting for desmin and alpha-smooth muscle actin form a single incomplete layer in the lamina propria of seminiferous tubules. Vimentin reactivity in the myofibroblasts and in the supporting Sertoli cells as well as Leydig cells in damaged testicular tissue was not observed. An increase in fibroblasts and free inflammatory cells positive for vimentin in the peritubular space on the peripheric area of the testis was observed.

Demonstration of intermediate filaments in sheep ovary.

Distribution patterns of intermediate filaments, vimentin, smooth muscle actin, and desmin were studied in the ovine ovary using an immunohistochemical method. Vimentin was consistently expressed in follicular cells of primary, secondary, and antral follicles. Stromal cells of cortex and medulla and those surrounding the corpus luteum were immunostained with the anti-vimentin antibody. Endothelial cells lining blood vessels showed strong anti-vimentin positivity. Smooth muscle cells positive for smooth muscle actin were incorporated in the cortical region in the theca interna and externa and formed incomplete spheres around large antral follicles. In atretic follicles, the presence of positive smooth muscle cells inside follicular spaces were related with capillaries. Corpora lutea were surrounded by a layer of positive smooth muscle cells. In the hilus, smooth muscle actin was localized in the wall of blood vessels. In cortical regions, desmin-positive cells were randomly distributed and occasionally formed ill-defined clusters around tertiary follicles, but not around secondary follicles, whereas desmin was expressed in the medullary region in blood vessels. The distribution pattern of intermediate filaments in sheep ovary suggests a possible role of smooth muscle cells in the mechanism of ovulation.