Benzo(a)pyrene inhibits ovulation in C57BL/6N mice

Area of Science:

• Reproductive toxicology
• Environmental health
• Endocrinology

Background:

• Female reproductive success depends on follicle growth, ovulation, and corpus luteum formation.
• Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants with potential reproductive toxicity.
• Benzo(a)pyrene is a well-studied PAH found in various environmental pollutants.

Purpose of the Study:

• To investigate the dose- and time-dependent effects of benzo(a)pyrene exposure on female mouse reproductive function.
• To determine the threshold and ED50 for benzo(a)pyrene's impact on corpora lutea.
• To assess the recovery patterns of reproductive parameters after benzo(a)pyrene exposure.

Main Methods:

• C57BL/6N female mice were administered single intraperitoneal injections of benzo(a)pyrene at doses from 1 to 500 mg/kg.
• The number of corpora lutea was quantified at various time points post-treatment (1, 2, 3, and 4 weeks).
• Dose-response relationships, including threshold and ED50, were calculated to assess toxicity and recovery.

Main Results:

• Benzo(a)pyrene caused a dose- and time-dependent decrease in corpora lutea number.
• The most significant effect was observed at 1 week post-treatment, with a threshold of 1 mg/kg and ED50 of 1.6 mg/kg.
• Partial recovery was noted by 2 weeks, with complete recovery by 3 weeks for doses below 100 mg/kg; however, higher doses (100-500 mg/kg) resulted in persistent reduction in corpora lutea.

Conclusions:

• Acute benzo(a)pyrene exposure can transiently impair follicle growth, ovulation, and corpus luteum formation in female mice.
• This impairment can lead to transient infertility, particularly at higher exposure levels.
• The findings suggest that PAHs may pose a risk to female reproductive health.