Chronic Lead Exposure Effects in the Cynomolgus Monkey (Macaca fascicularis) Testis

Although reproductive consequences of high circulating blood lead levels (> or = 60 micrograms/dL) have been reported, potential adverse effects of chronic lead exposure in males that result in low to moderate blood lead levels (10-25 and 26-60 micrograms/dL, respectively) are unknown. Effects of chronic lead exposure to testis ultrastructure were determined in the cynomolgus monkey after oral administration of lead acetate (1500 micrograms/kg BW/day) in a vehicle in the following groups: from birth to 10 years (lifetime), postnatal day 300 to 10 years (postinfancy), and postnatal day 0-400 (infancy); monkeys in the control group received only the vehicle (95% glycerol and 5% distilled water). At age 10 years, circulating lead concentrations in lifetime and postinfancy-dosed monkeys were approximately 35 micrograms/dL, and in control and infancy animals the concentrations were < 1.0 microgram/dL. Sertoli and spermatogenic cells of dosed monkeys from the infancy and lifetime groups revealed injuries. Chronic exposure to lead that results in moderate blood lead concentrations induced persistent ultrastructural alterations in the cynomolgus monkey testis. Results of this study on the primate, following extrapolation to humans, could influence further refining of the impact of environmental lead contamination concentrations vis-à-vis the health of children, adults, and aged human beings.