Electron microscopical picture of sheep and goat embryos after freezing by vitrification
2001
Pivko, J. | Kubovicova, E. | Oberfranc, M. (Vyskumny Ustav Zivocisnej Vyroby, Nitra (Slovak Republic))
Early goat and sheep embryos (n = 38) were frozen in vitrification solution with ethylene glycol. The own freezing consisted of two steps. First the embryos were transferred for five minutes to the equilibration solution (20% ethylene glycol) and then for 20-30 seconds they were exhibited to the influence of vitrification solution (solution of 40% ethylene glycol, 20% FCS, 40% 2M sucrose). Then, directly gradually freezing and storage in liquid nitrogen were made. Thawed sheep and goat embryos were evaluated by light and electron microscopes. Portion of damaged embryos after thawing, embryos evaluated by light and electron microscopes presented in sheep 13.92%, in goats 12.96% and by electron microscopy 29.40% and 25.71% respectively. Damages of organelles of trophoblastic and embryoblastic cells which were the most often manifested by disintegration of cytoplasmatic membranes and by creation of hyaline rings were detected by ultrastructural study. Disintegration of shelves and increase of electronoptical density of mitochondria content were observed in the form of round black bodies. In the cells of trophoblast and embryoblast was found the occurrence of multivesicular and residual bodies and autophagical vacuoles. On the base of electronoptical analysis of vitrified sheep and goat embryos it is necessary to calculated with more than 25% losses of embryos after the transfer as the results of destruction of membranes and mitochondria and also as the consequence of increased occurrence of cytoplasmatic lysosomal structures
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