Comparison of developmental and morphological properties of mouse embryos and parthenotes

This study is based on the ethical and legal obstacles about using humanembryos in experimental studies in vitro. In this work, developmental andmorphological properties of mouse embryos obtained by natural fertilization andparthenotes produced by parthenogenetic activation protocols were determined tocompare the probability of using parthenotes instead of embryos.We used 80 female and 20 male mice. Naturally fertilized preimplantationstage embryos and diploid parthenotes activated in the medium containing SrCl2and Cytochalasin B were obtained from female mice after superovulationprotocols. These two groups were monitored by light and electron microscopictechniques to evaluate their developmental aspects and ultrastructural features.The rate of development of pronuclear embryos on the first day was 89.19%and the rate that reached the blastocyst stage on the 5th day was 43.24%. Thesuccess rate of activation of the mature oocytes picked up from oviducts was31.88%. On day 4, 3.75% of the parthenotes were still alive and 2 of them (%2.50)reached the morula stage. The developmental potential of parthenotes reduced inthe progressive days when compared with the developmental potential of theembryos. Both embryos and parthenotes owned organelle groups in cortical, midand perinuclear reigons. These organelle groups included mitochondria, lipiddroplets, lisosomal structures, ribosomes, smooth and granular endoplasmicreticulum, fibrillar lattice and vesicles. Moreover, multivesicular bodies, myelinfigures and crystalloids became visible in advanced stage embryos and even earlierin parthenotes. Crystalloid related organelle-free areas attracted attention inparthenotes which began to be visible in the earlier stages.In conclusion, the developmental potentials of embryos and parthenotesespecially in the early stages were statistically similar and significant (p=0,98102).But in the following days, light microscopic observations according to the criteriaof blastomere size and regularity, cytoplasmic granularity and fragmentationrevealed that growth retardation in the developmental potential of parthenotes wasconspicious. Also, ultrastructurally, degenerative signs such as increased myelinfigures, multivesicular bodies, crystalloids, organelle-free areas; in addition to thedecreased amount of organelles in perinuclear regions were evaluated earlier indevelopmental stages of parthenotes compared to embryos.