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Mouse Oocyte Microinjection, Maturation and Ploidy Assessment
Published on: July 23, 2011
Oocyte aneuploidy screening using superovulating prepubertal mice: effect of methotrexate
Teratology
|December 1, 1981
Summary
Superovulating young mice provides a reliable source of oocytes for aneuploidy testing. This method shows low background aneuploidy and increased hypoploidy when exposed to methotrexate, suggesting potential for environmental agent screening.
Area of Science:
- Reproductive biology
- Cytogenetics
- Developmental toxicology
Background:
- Numerical chromosomal aberrations (aneuploidy) are a significant cause of pregnancy loss and birth defects.
- Effective cytogenetic methods are crucial for understanding the causes of nondisjunction in mammalian gametes.
Purpose of the Study:
- To evaluate the yield of scorable oocytes from superovulated prepubertal mice using a double fixation technique.
- To determine the baseline aneuploidy level in these oocytes.
- To assess the sensitivity of these oocytes to aneuploidy induction by methotrexate.
Main Methods:
- Superovulation was induced in 22-24 day old C129F1 hybrid mice using pregnant mare serum and human chorionic gonadotropin (HCG).
- A double fixation procedure was adapted for mouse oocytes.
- Methotrexate was administered to induce aneuploidy, with oocytes recovered 15 hours post-HCG.
Main Results:
- A high yield of chromosomally scorable ova (average 9.5 per mouse) was achieved.
- The background level of aneuploidy was very low (0/465 hyperploid).
- Methotrexate significantly increased hypoploidy but not hyperploidy.
Conclusions:
- Superovulating young mice offers an economical and convenient source of oocytes for aneuploidy studies.
- This model shows promise for screening environmental agents for aneuploidy-inducing potential.
- Further research is needed to fully establish the susceptibility of these oocytes to aneuploidy induction.
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