Sang-Yong Choe

Differential gene expression patterns in porcine nuclear transfer embryos reconstructed with fetal fibroblasts and mesenchymal stem cells

The present study compared the developmental ability and gene expression pattern at 4‐cell, 8‐cell, morula, and blastocyst stages of porcine nuclear transfer (NT) embryos from fetal fibroblasts (FFs) and mesenchymal stem cells (MSCs), in vitro fertilized (IVF), and in vivo derived embryos. MSC‐NT embryos showed enhanced blastocyst formation, higher total cell number, and a low incidence of apoptosis compared to FF‐NT embryos. Alterations in the expression pattern of genes implicated in transcription and pluripotency (Oct4, Stat3, Nanog), DNA methylation (Dnmt1, Dnmt3a), histone deacetylation (Hdac2), growth factor signaling, and imprinting (Igf2, Igf2r) and apoptosis (Bax, Bcl2) regulation were observed in NT embryos. The expression of transcripts in MSC‐NT embryos more closely followed that of the in vivo derived embryos compared with FF‐NT embryos. In conclusion, MSCs with a relatively undifferentiated genome might serve as suitable donors that could be more efficiently reprogrammed to re‐activate expression of early embryonic genes in porcine NT. Developmental Dynamics 236:435–446, 2007.

Enhanced cryosurvival of bovine blastocysts produced in vitro in serum-free medium.

AbstractPurpose: Culture systems affect the development of IVP embryos and consequently their cryosurvival potential. The viability of postthawed bovine IVP embryos developed from IVM/IVC medium in the presence or absence of serum was compared.nMethods: Cumulus-oocyte complexes were matured in IVM medium supplemented with or without serum. Some oocytes were evaluated for nuclear maturation status and others were inseminated with semen. Presumptive zygotes were cultured in IVC medium supplemented with or without serum for 9 days. Blastocysts were cryopreserved with 1.5 M ethylene glycol in PBS.nResults: No difference was observed in the nuclear maturation status and cleavage rates in both groups, but significantly (P < 0.05) higher in blastocyst rates in the serum-supplemented group. After freezing, survival of blastocysts was higher in the serum-free group. At 36 h culture after thawing, blastocysts developed without serum had significantly (P < 0.05) higher cell number than those cultured with serum.nConclusions: We conclude that serum-free culture system enhances the viability of frozen-thawed bovine embryos.

Follicular fluid enhances sperm attraction and its motility in human.

AbstractPurpose: Follicular fluid has a pivotal effect on motility and chemotaxis of spermatozoa for successful fertilization. The effect of human follicular fluid (hFF) and progesterone on attraction and motility of spermatozoa were investigated using simplified capillary assays.nMethods: Capillary tubes loaded with hFF, modified human tubal fluid (m-hTF), or m-hTF supplemented with progesterone, respectively, were used for assessments of attraction and motility of spermatozoa following culture at various time intervals.nResults: Number and motile ratio of spermatozoa in the tubes loaded with hFF were significantly (P < .05) higher than those with m-hTF. In the tubes loaded with m-hTF, m-hTF supplemented with progesterone, and hFF, the attracted number of spermatozoa were 34 × 105, 131 × 105, and 108 × 105, and motile ratio of spermatozoa was 37, 48, and 82%, respectively.nConclusions: We conclude that hFF clearly plays a crucial role in enhancing attraction and motility of spermatozoa, and progesterone has strong effect on attraction of spermatozoa.