Increased frequency of chromosome congression defects and aneuploidy in mouse oocytes cultured at lower temperature

Abstract

Optimal culture conditions are essential for successful IVM of mammalian oocytes and for their further development into an embryo. In the present study we used live cell imaging microscopy to assess the effects of suboptimal culture temperature on various aspects of IVM, including duration of meiosis I, dynamics of polar body extrusion, chromosome congression, anaphase-promoting complex/cyclosome (APC/C) activation and aneuploidy. The data showed that even a small deviation from the optimal incubation temperature causes marked changes in the duration and synchronicity of meiosis, APC/C activity and the frequency of chromosome congression and segregation errors. In vitro manipulation and maturation of germ cells is widely used in both human and animal artificial reproduction techniques. Mammalian oocytes are naturally prone to chromosomal segregation errors, which are responsible for severe mental and developmental disorders. The data presented herein demonstrate that exposure of mouse oocytes to suboptimal temperature during manipulation and maturation could further increase the frequency of chromosome segregation defects in these cells.