Chlorpyrifos induced reproductive toxicity in male mice

The reproductive toxicity of the insecticide chloropyrifos was studied in male mice. Adult male mice were treated by gavage with chloropyrifos at doses of 0, 5, 15, and 25 mg/kg-d for 4 weeks before mating with untreated females. Signs of cholinergic effects were observed in the 15 and 25 mg/kg-d treated groups. Brain and skeletal muscle acetylcholinesterase activity was inhibited in the same groups. Chloropyrifos treatment was associated with a decreased number of live fetuses, and an increased number of dead fetuses at 25 mg/kg-d. The number of early resorption was decreased in both 15 and 25 mg/kg-d treated groups. The percent morphologically normal spermatozoa were affected in 15 and 25 mg/kg-d dose groups; however, sperm motility and count were decreased in the same treated groups compared to the control. Histologic examination of brain revealed histological abnormalities in the middle and high groups. Dose related histologic changes, including degeneration of muscle fibers, were observed in the muscles of male mice treated with all the doses of chloropyrifos. The current study demonstrated adverse effects of male chloropyrifos exposure on pregnancy outcome with effects on sperm parameters at 15 and 25 mg/kg-d.