ToxSci Advance Access originally published online on September 16, 2004
Toxicological Sciences 2004 82(2):590-597; doi:10.1093/toxsci/kfh277
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Toxicological Sciences vol. 82 no. 2 © Society of Toxicology 2004; all rights reserved.
Exposure to Trichloroethylene and its Metabolites Causes Impairment of Sperm Fertilizing Ability in Mice
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* Ottawa Health Research Institute, Hormones, Growth, Development, and Department of Biochemistry/Microbiology/Immunology, University of Ottawa, Ottawa, Ontario, Canada K1Y 4E9; The Ottawa Hospital, and Department of Obstetrics and Gynecology, Division of Reproductive Medicine, University of Ottawa, Ottawa, Ontario, Canada K1Y 1J8; Department of Anatomy and Cell Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6; and Environmental Health Research Division, Health Canada, Tunney's Pasture, Ottawa, Canada K1A 0L2
Received May 21, 2004; accepted August 26, 2004
Trichloroethylene (TCE) is a prevalent occupational and environmental contaminant that has been reported to cause a variety of toxic effects. Here, we have undertaken studies to test the hypothesis that TCE exposure adversely affects sperm function and fertilization. Sperm retrieved from mice exposed to TCE (1000 ppm) by inhalation for 1 to 6 weeks were incubated in vitro with eggs isolated from superovulated female mice. The number of sperm bound per egg was significantly decreased when mice were exposed to TCE for 2 and 6 weeks but not at exposures of 1 and 4 weeks. In vivo fertilization was also determined in superovulated female mice mated with males exposed to TCE for 2 to 6 weeks. The percentages of eggs fertilized, as assessed by the presence of two pronuclei, were significantly decreased after 2 and 6 weeks of TCE exposure. A slight but insignificant decrease was observed after 4 weeks of TCE exposure. The direct effects of TCE and its metabolites, chloral hydrate (CH) and trichloroethanol (TCOH), on in vitro sperm–egg binding were also investigated. Sperm–egg binding was significantly decreased when sperm were pretreated with CH (0.1–10 µg/mL). Significantly lower levels of sperm–egg binding were also detected with TCOH (0.1–10 µg/mL), although the decreases were not as pronounced as those for CH. These results showed that TCE exposure leads to impairment of sperm fertilizing ability, which may be attributed to TCE metabolites, CH, and TCOH.
Key Words: trichloroethylene; chloral hydrate; fertilization; sperm–egg binding; trichloroethanol.