ABSTRACT
Ten adults [three months old] male albino rats weighing 250-300gm were used in this study aiming to get insight on the histological alterations in the testes of chronically lead exposed adult rats in an attempt to clarify the mechanism of action of lead on the male reproductive system. The animals were divided into two equal groups, a control group and an experimental one. Animals of the first group were injected intraperitoneally by an equivalent doses of normal saline. Animals of the second group were injected intraperitoneally by lead acetate at a dose of 8mg/kg body weight/day, 5days/week for five successive weeks. At the time of sacrifice, the animals were anaesthetized with ether inhalation and their testes were carefully dissected and processed for light and electron microscope examination. Light microscope examination of the testes of lead treated rats revealed the presence of irregularities in the outlines of the affected seminiferous tubules, disorganization and sloughing of their germinal epithelium into their luminae. Also, there was arrest of spermatogenesis in most of the affected tubules. Electron microscope examination of the testes of the lead treated rats showed that some of spermatogonia appeared with large vacuoles and distorted nuclei. The nuclei of primary spermatocytes showed loss of their membranes and fragmentation of their chromatin. The spermatids had few mitochondria, large lysosomes and degenerated nuclei. While Sertoli cell cytoplasm contained large vacuoles and distorted mitochondria. Also, there was disruption of tight junction between their lateral processes. The midpieces of the sperms revealed markedly affected axonemes and both fibrous and mitochondrial sheathes. The cytoplasm of Leydig cells contained many vacuoles, few lipid droplets and their nuclei had much peripheral heterochromatin. From this study, it could be concluded that lead has a harmful effect on the male reproductive system through a direct influence on the histological structure of the testis