Bo-Hyun Kim

Wonkwang University, Iksan, North Jeolla, South Korea

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Publications (2)1.54 Total impact

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    ABSTRACT: The accelerated cooling rate associated with vitrification reduces injuries attributed to cryopreservation and improves the post-freezing developmental competence of vitrified embryos. In this study, embryos were vitrified and warmed and morphologically evaluated for their development to blastocysts. Survival rates between the fresh (96.7%±3.8%) and vitrified embryos (90.7%±5.1%) did not differ significantly (P>0.05). The mitochondrial membrane potential of fresh control cells measured by 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolyl carbocyanide iodide staining was similar to that of cryoprotected and vitrified embryos. Mitochondrial staining with rhodamine 123 did not differ among the fresh, cryoprotected, and vitrified embryos. Moreover, the distribution of H2O2, assessed by 2′,7′-dichlorodihydrofluorescein diacetate staining, did not differ among the groups. The results showed that the developmental rate did not differ significantly among the fresh (87.8%±11.3%), cryoprotected (83.2%±7.6%), and vitrified 2-cell embryos (75.8%±14.2%). The mean number of the inner cell mass (ICM), trophectoderm (TE), and apoptotic cells was counted and statistically compared, and although the number of ICM and TE was decreased in the cryoprotected and vitrified embryos, there were no significant differences among the groups (P>0.05). During the cultivation period, randomly selected blastocysts from each group were stained using either 4′,6-diamidino-2-phenylindole and bisbenzimide or the terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling technique. The incidence of apoptosis appeared to be almost identical in all the groups. Droplet vitrification could subsequently lead to high survival and developmental rates of cryopreserved mouse embryos.
    Animal Cells and Systems - ANIM CELLS SYST. 01/2011;
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    ABSTRACT: Gangliosides are a family of sialic acid-containing glycosphingolipids that are abundant in neurons and have a variety of functions in developing and mature tissues. We examined the expression of ganglioside GT1b in the embryonic preimplantation stage after freezing and thawing processes to determine the regulatory roles of ganglioside GT1b in early embryonic development. ICR mouse embryos at the two-cell stage obtained by flushing the oviducts were frozen by two cryopreservation procedures, slow freezing using a programmable freezer or vitrification by direct plunging into liquid nitrogen. Slow freezing was conducted with equilibration in 1.5 M 1,2-propanediol or 5% equilibration glycerol. Vitrification was applied with a 10-15 min equilibration in 7.5% ethylene glycol (EG), 7.5% dimethylsulfoxide (DMSO), and 30 sec in a solution of 15% EG, 15% DMSO and 0.5 M sucrose. Immediately after thawing, the survival rate of the embryos was assessed by their morphology and ability to develop to blastocysts in culture. The survival rate of vitrified and thawed embryos (92%) was significantly higher than that of slow frozen and thawed embryos (76%) (P<0.05). A tendency of higher blastocyst rate was found in the vitrified and thawed embryos compared to that of the slow frozen and thawed embryos. Confocal immunofluorescence staining confirmed that surviving embryos expressed ganglioside GT1b, with the strongest expression at the compacted eight-cell or later stage embryos. Ganglioside GT1b was not observed in the TUNEL-positive, apoptotic embryos, suggesting that cryopreservation had induced DNA breaks in them. These results suggest that ganglioside GT1b may play an important role in embryo survival or development.
    Archives of Pharmacal Research 01/2008; 31(1):88-95. · 1.54 Impact Factor