Effects of Bisphenol A and 4-tert-octylphenol on the embryo implantation in mice

Epidemiological studies suggested that exposure to cigarette smoke early in life is associated with long-term health risks. Using a nuclear factor erythroid 2-related factor 2 (Nrf2) knockout (KO) mouse model, we found the sperm concentration and sperm motility were significantly lower in mice exposed to cigarette smoke extract (CSE) beginning at 4 weeks of age compared to 8 week-old mice. Additionally, CSE exposure significantly decreased in vitro fertilization (IVF) and blastocyst rates in the Nrf2 KO mice compared to the wild-type (WT) mice. Exposure to CSE resulted in the highest expression of the antioxidant genes in the CSE-treated WT mice at 8 weeks of age, and it was the lowest in the CSE-treated KO mice at 4 weeks. The study concluded that puberty exposure to CSE significantly affects adult spermatogenesis in agreement with the antioxidant Nrf2 genotype.