Examination of the reproductive effects of tricresyl phosphate administered to Long-Evans rats

Tricresyl phosphate (TCP) is used commercially as a plasticizer and a flame retardant. The reproductive effects of TCP (less than 9.0% TOCP) were examined. Male Long-Evans rats received 0, 100, or 200 mg/kg and females received 0, 200, or 400 mg/gk TCP in corn oil by gavage. The 100 mg/kg TCP males were mated with 200 mg/kg TCP females, and 200 mg/kg TCP males were bred with 400 mg/kg TCP females. Males were dosed for 56 days and females for 14 days prior to breeding and throughout the 10-day breeding period. Following breeding, the males were necropsied and evaluated for sperm parameters and reproductive tract histopathology. Females were dosed throughout gestation and lactation. Pups and adult females were necropsied on postnatal day 21. Sperm concentration, motility, and progressive movement were decreased for 200 mg/kg dose group males. A dose-dependent increase in abnormal sperm morphology was observed for males in both TCP dose groups. The percent of sperm-positive females per group was unchanged, but the number of females delivering live young was severely decreased by TCP exposure. Litter size and pup viability were decreased in the 400 mg/kg dose group. Pup body weight and developmental landmarks were unaffected by TCP exposure. Histopathologic changes were observed in the testes and epididymides of male rats and in the ovaries of female rats exposed to TCP.