Oocyte enucleation by 795 nm femtosecond laser is a precise and effective method of recipient cytoplast preparation

Oocyte enucleation by femtosecond (fs) laser radiation is low-invasive and effective method of recipient cytoplast preparation. We have already demonstrated an ability to completely eliminate the metaphase plate by the fs laser without significant oocyte morphology and viability impairment. Considering further development of femtosecond laser oocyte enucleation for artificial reproductive technologies in humans and for the somatic cell nuclear transfer in mammals, the persistence of any DNA fragments after the fs laser enucleation must be studied thoroughly. In this work we revealed the remains of the metaphase plate by super resolution confocal microscopy after the laser  enucleation of mouse oocytes at metaphase II stage. The laser was set up on 795 nm in 80 MHz mode with 0,5 nJ pulse energy. By the super resolution microscopy (Airyscan 2) we have detected minor fragments of the metaphase plate in the laser-exposed oocytes. However, the careful laser treatment is able to provide the recipient cytoplast without any detectable DNA fragments.