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Updated: May 23, 2026
Culture and Co-Culture of Mouse Ovaries and Ovarian Follicles
Published on: March 17, 2015
Methoxychlor-induced ovarian follicle toxicity in mice: dose and exposure duration-dependent effects
Tessie Paulose1, Lawrence V Tannenbaum, Christina Borgeest
1Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
Background:
Methoxychlor (MXC) is specifically known to target ovarian antral follicles, increasing atresia (death via apoptosis) in them. This is of concern because females are born with a finite pool of ovarian follicles. Only limited studies have explored the phenomenon of a reduced fertility threshold for effect based on the percentage of antral follicle atresia.
Methods:
In this article, we report on adult female CD-1 mice exposed intraperitoneally to various doses of MXC for 5, 10, 20, and 30 days. In the 20-day treatment, mice were dosed with either the vehicle or MXC at 64 or 96 mg/kg/day, whereas in the 30-day treatment, mice were dosed with vehicle or MXC at 48, 64, or 96 mg/kg/day. The mice that were dosed with MXC for 30 days were also mated with untreated males for a determination of overall fertility.
Results:
A significantly increased percentage (50%) of atretic antral follicles was observed only after 20 and 30 days of treatment. Specifically, mice treated with MXC64 for 20 and 30 days had an increased percentage of atretic antral follicles compared with vehicle-treated mice. Interestingly, mice dosed with MXC96 had an increased percentage of atretic antral follicles after 30 days, but not after 20 days of treatment compared with vehicle-treated mice. Overall fertility of the mice was not different compared with controls.
Conclusions:
The results indicate that as much as a 50% increase in atretic antral follicles does not affect the immediate fertility of the mice.
Insights
Methoxychlor (MXC) exposure increased ovarian follicle atresia in mice, but a 50% increase in cell death did not impact immediate fertility. Further research is needed on long-term reproductive effects.
Area of Science:
- Reproductive Toxicology
- Endocrinology
- Environmental Health
Background:
- Methoxychlor (MXC) is an environmental contaminant known to induce ovarian follicle atresia.
- Females possess a finite pool of ovarian follicles, making them vulnerable to agents that increase atresia.
- Limited data exists on the fertility threshold related to increased antral follicle atresia.
Purpose of the Study:
- To investigate the impact of MXC exposure on ovarian follicle atresia in adult female mice.
- To determine if increased atresia affects immediate female fertility.
Main Methods:
- Adult female CD-1 mice were administered intraperitoneal injections of MXC at varying doses and durations (5, 10, 20, 30 days).
- Specific treatment groups received MXC at 48, 64, or 96 mg/kg/day for 30 days.
- Fertility was assessed by mating MXC-treated mice with untreated males.
Main Results:
- A significant increase in atretic antral follicles (up to 50%) was observed after 20 and 30 days of MXC treatment.
- Mice treated with MXC (64 mg/kg/day) for 20 or 30 days showed higher atresia rates compared to controls.
- While MXC (96 mg/kg/day) increased atresia after 30 days, no significant effect was noted at 20 days.
- Overall fertility in MXC-exposed mice did not differ from the control group.
Conclusions:
- A substantial increase in ovarian antral follicle atresia induced by MXC does not compromise immediate fertility in mice.
- These findings suggest a potential resilience of the reproductive system to acute toxicant-induced follicle loss.
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