Effects of dynamic oxygen concentrations on the development of mouse pre- and peri-implantation embryos using a double-channel gas supply incubator system / 대한생식의학회지

OBJECTIVE: We aimed to evaluate the effects of different oxygen conditions (20% [high O₂], 5% [low O₂] and 5% decreased to 2% [dynamic O₂]) on mouse pre- and peri-implantation development using a novel double-channel gas supply (DCGS) incubator (CNC Biotech Inc.) to alter the oxygen concentration during in vitro culture.METHODS: The high-O₂ and low-O₂ groups were cultured from the one-cell to the blastocyst stage under 20% and 5% oxygen concentrations, respectively. In the dynamic-O₂ group, mouse embryos were cultured from the one-cell to the morula stage under 5% O₂ for 3 days, followed by culture under 2% O₂ to the blastocyst stage. To evaluate peri-implantation development, the blastocysts from the three groups were individually transferred to a fibronectin-coated dish and cultured to the outgrowth stage in droplets.RESULTS: The blastocyst formation rate was significantly higher in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group. The total cell number was significantly higher in the dynamic-O₂ group than in the low-O₂ and high-O₂ groups. Additionally, the apoptotic index was significantly lower in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group. The trophoblast outgrowth rate and spread area were significantly higher in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group.CONCLUSION: Our results showed that a dynamic oxygen concentration (decreasing from 5% to 2%) had beneficial effects on mouse pre- and peri-implantation development. Optimized, dynamic changing of oxygen concentrations using the novel DCGS incubator could improve the developmental competence of in vitro cultured embryos in a human in vitro fertilization and embryo transfer program.

Molecular Cloning of hSC2 Encoding 5α-reductase-like Protein

BACKGROUND: The human homologue of the SC2 gene from a human dermal papilla cell cDNA library has been isolated and designated hSC2. HSC2 protein also shares similarity with 5 -reductase, a protein important in testosterone metabolism. OBJECTIVE: Prior to knowing the functions of hSC2 in dermal papilla, we cloned it and analyzed its relative expression levels in adult tissues and cancer cell lines. METHODS: hSC2 was isolated from low abundant clones in dermal papilla cDNA library using cDNA array hibridization method. Full-length clone was sequenced and we studied its expression in different tissues by Northern blot hybridization. RESULTS: Sequence data reveals a single open reading frame, encoding a putative hydrophobic protein with a calculated molecular weight of 36 kDa. Its deduced amino acid sequences are almost 97.4% identical to t4ose of rat protein. Northern blot hybridization shows that hSC2 cDNA recognizes a 1.35 kb transcript that was expressed in various epithelial and mesenchymal tissues including testis and liver. CONCLUSION: We have cloned and analysed tissue distributions of hSC2. It was interesting that it had homology with 5α-reductase isozymes. Further studies will be needed to understand the involvement of hSC2 in androgen hormone signaling.