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Updated: Aug 19, 2026
Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes
Published on: September 13, 2022
Non-invasive method to assess genotoxicity of nocodazole interfering with spindle formation in mammalian oocytes
Ying Shen1, Ilse Betzendahl, Fengyun Sun
1Faculty of Biology, Institute of Gene Technology/Microbiology, University of Bielefeld, D-33501 Bielefeld, Germany.
Abstract:
Trisomies due to nondisjunction in oogenesis are still a major cause of genetic diseases in humans. In this study, we analysed spindle morphology of in vitro matured nocodazole-exposed mouse oocytes by novel non-invasive Polscope-microscopy, and compared images to those obtained by anti-tubulin immunofluorescence of fixed oocytes. Polscope revealed a reduction in the numbers of oocytes expressing a birefringent spindle, and alterations in spindle morphology at concentrations of nocodazole below those inducing detectable aberrations in immunofluorescence. Hyperploidy increased significantly at a concentration of 40 nM nocodazole in mouse metaphase II oocytes, similar to thresholds inducing nondisjunction in cultured human lymphocytes. In conclusion, Polscope represents a novel highly sensitive, non-invasive method to identify chemicals inducing severe spindle aberrations that predispose mammalian oocytes to nondisjunction. Polscope may provide information on the functionality of the spindle in experimental studies but is also compatible with clinical trials in human assisted reproduction due to its non-invasive nature.
Insights
Polscope microscopy offers a sensitive, non-invasive method to detect spindle aberrations in oocytes, crucial for understanding genetic diseases caused by nondisjunction.
Area of Science:
- Reproductive Biology
- Genetics
- Microscopy
Background:
- Nondisjunction during oogenesis is a primary cause of human genetic disorders.
- Assessing oocyte spindle integrity is vital for reproductive health.
Purpose of the Study:
- To evaluate the efficacy of non-invasive Polscope microscopy in analyzing spindle morphology.
- To compare Polscope findings with traditional immunofluorescence methods.
- To identify chemical agents that induce spindle aberrations leading to nondisjunction.
Main Methods:
- In vitro matured mouse oocytes were exposed to varying concentrations of nocodazole.
- Spindle morphology was analyzed using non-invasive Polscope microscopy.
- Images were compared with anti-tubulin immunofluorescence of fixed oocytes.
Main Results:
- Polscope detected spindle aberrations at lower nocodazole concentrations than immunofluorescence.
- A significant increase in hyperploidy was observed at 40 nM nocodazole.
- Polscope identified reduced birefringent spindle expression and altered spindle morphology.
Conclusions:
- Polscope microscopy is a highly sensitive, non-invasive tool for identifying chemicals that cause spindle aberrations and predispose oocytes to nondisjunction.
- This method can inform experimental studies on spindle function and is applicable to clinical assisted reproduction.
- Polscope offers a promising approach for assessing risks associated with chemical exposures impacting female fertility.
