Effect of 2,3,7,8 - tetrachlorodibenzo- p-dioxin (TCDD) on spermatogenesis and Leydig cell volume in adult rats

Abstract

Exposure to 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) alters testicular function; however, its effect on daily sperm production and Leydig cell volume has not been determined in adult rats. Adult male Sprague-Dawley rats (300–350 g) received 0, 12.5, 25.0, or 50.0 μg/kg body weight doses of TCDD by a single intraperitoneal injection. The body weight was reduced (P < 0.01) in a dose-dependent fashion. Testicular weight and daily sperm production per testis were not significantly reduced by TCDD. The number of androgen receptors in the testis or in the urogenital sinus was not affected by TCDD treatment. Weights of two androgen-sensitive organs (seminal vesicles and epididymis) were reduced (P < 0.01) in a dose-dependent fashion. Rats in Exp. 1 tended (P > 0.05) to have reduced Leydig cell volume after TCDD treatment, and rats in Exp. 2 revealed a dose-dependent reduction (P < 0.01) in volume per testis of Leydig cell cytoplasm, nuclei, or total Leydig cell volume. While TCDD had a dose-related effect on Leydig cell volume and function, a sufficient amount of testosterone apparently was present to quantitatively maintain spermatogenesis during the mitotic activity of spermatogonia and the final developmental events of spermatids for at least four weeks in adult rats.