Chronic lead exposure induces ultrastructural alterations in the monkey seminal vesicle

Lead is a toxic and carcinogenic metal that has been extensively associated with male reproductive abnormalities. The purpose of this study was to establish the effects of lead on the primate seminal vesicle. Sixteen cynomolgus monkeys maintained in environmentally controlled conditions were orally administered gelatin capsules containing 1500 micrograms lead acetate/kg bw/day. Monkeys were randomly assigned to the following groups: control (n = 3) which received 95% glycerol and 5% distilled water (vehicle) over their lifetime, infancy (limited to the first 400 days of life; n = 4), post-infancy (dosed following 300 days of life to 9 years of age; n = 5) and lifetime exposure (9 years; n = 4). At necropsy, the seminal vesicles from each animal were removed, fixed in glutaraldehyde, and processed for ultrastructural analysis by conventional methods. The glands from animals in the control group consisted of acini lined by two cell types, viz., tall columnar secretory cells, and round basal cells. Secretory cells possessed microvilli, basally located nuclei surrounded by much rough endoplasmic reticulum, a few lipid droplets, and supra-nuclear regions dominated by pleomorphic membrane-limited secretory granules. All the treated groups exhibited an augmentation in the number of lipid droplets within the secretory cells. In both the infancy and post-infancy groups, a marked reduction in electron-dense cores of the secretory droplets was observed in severely affected regions of the glands. These findings support the evidence that lead is a potent reproductive toxicant, however, further research is needed to determine the consequences of this damage on reproductive performance.