Khromenkova O. Cytogenetic analysis of mammalian embryos after influence the various factors of cryopreservation

The thesis is devoted to the problem of effect of the cryopreservative factors (glycerol solutions, hypothermia and freezing with different rates) on the viability, mitotic mode and chromosome set of 2-8-cell mouse embryos. The division increases the stability of embryos to the temperature decreasing. The exposure in glycerol solutions does not increase the aneuploidy rate in embryos of different stages. The procedure of rapid freezing provides higher integrity of blastomeres of 8-cell embryos and does not decrease the viability, compared with slow program freezing. By cytological and cytogenetic methods it was revealed that cryopreservation of 8-cell embryos regardless of freezing method and their compaction degree does not influence on the aneuploidy rate, but changes the spectrum of mitotic abnormalities. Electronic-microscopic study has shown that 8-cell embryos are mainly characterized by the integrity of ultrastructure of nuclei and of the main cytoplasmic organelles after rapid freezing .