ИСТИНА

Aneuploid-diploid mosaics are embryos that consist of aneuploid and diploid cells. Aneuploid cells appear in the mosaic preimplantation embryo as a result of chromosomal abnormalities during the first mitotic divisions. With the spread of preimplantation genetic screening (PGS) in IVF clinical practice, it has been shown that mosaicism is a very common phenomenon for preimplantation embryos. The effect of mosaicism on implantation and the developmental potential of embryos is not well understood. Currently, in IVF mosaic embryos, characterized by the presence of a mixture of diploid and aneuploid cell lines, are usually not used, since they are considered abnormal. However, several facts, including clinical cases of the birth of healthy infants after mosaic embryo transfer, served as the basis for the hypothesis that during embryogenesis during, there are mechanisms of self-correction, resulting in the restoration of the embryo euploidy. Experimental tests of this hypothesis were not actually carried out. The scientific problem addressed by the project is to study the potency for self-correction of aneuploidy and the normal development of mosaic diploid / aneuploid human embryos at peri-implantation developmental stages. Thus, the results obtained during the project will have scientific novelty. Human embryos carrying chromosomal abnormalities, including mosaics, were used in the study. With the use of a model object - mouse embryos, we have now debugged the technique of implantation of human blastocysts in vitro using highly adhesive plastic surfaces. Observation of the in vivo morphology of developing embryos is carried out using a light microscope. Confocal microscopy is used to study the processes of cell death and proliferative activity in mosaics to identify the processes of replacement of aneuploid clones by diploid cells as a result of possible self-correction of human mosaic embryos. Biopsies of various structures of the embryos will be dissected via micromanipulation system. It is planned to carry out molecular karyotyping of biopsies to identify aneuploidy / diploid status of different cell populations of embryos. In the course of the work, as the results it is expected to obtain actual data on developmental disorders in the peri-implantation period of human embryos (including aneuplod/diploid mosaics) with specific chromosomal abnormalities. Experimental data will also be obtained to confirm or deny the initial hypothesis that the restoration of the diploid status of the embryo occurs in the peri-implantation period of development. Finally, prognostic assessments of the possibility of normal development of embryos with different variants of mosaic aneuploid/diploid genotype will be given. According to various clinical data, the percentage of mosaic embryos varies very widely-from 5 to 60-65%, so the study of the potential for the development of such embryos is an important medical problem in the practice of assisted reproductive technologies. The solution of these problems will create a fundamental scientific basis for improving methods for assessing the quality of the embryo and to eliminate errors in the selection of the embryo for transfer in clinical practice of ART.