The aim of this study was to investigate the effect of uterine histotroph on embryo development and the expression of cysteine-rich protein 2 (CRP2), coatomer subunit gamma-2 (G2COP), myoglobin (MYG), vascular endothelial growth factor D (VEGFD), collagen alpha 4 chain (COL4) and galactoside 3-L-fucosyltransferase 4 (FUT4) proteins in porcine embryo during pre-implantation. Uterine histotroph (UH) was collected from uterine horn on corpus albican phase, and embryos were cultured in porcine zygote medium with UH for 168 hours. Cleavage and blastocyst formation of embryo were detected at 168 hours after in vitro fertilization. And CRP2, G2COP, MYG, VEGFD, COL4 and FUT4 proteins were observed using confocal laser microscope. In results, embryo cleavage rate was not significantly changed by UH, but blastocyst rate was significantly (P<0.05) decreased in UH-treated embryos. Moreover, CRP2, G2COP, MYG, VEGFD, COL4 and FUT4 proteins were expressed in blastomere. CRP2 in embryo was significantly overexpressed (P<0.05), but not G2COP, MYG, VEGFD, COL4 and FUT4 proteins. In summary, UH on corpus albican phase was increased CRP2 protein in embryo, and inhibited blastocyst formation in preimplantation porcine embryos, suggesting that CRP2 may play an interrupter on embryo development in pigs.

Introduction
 Materials and Methods
  1. Collection of uterine histotorph (UH)
  2. In vitro fertilization
  3. Immunofluorescence
  4. Statistical analysis
 Results
  1. Effect of UH on embryo development and blastocyst in pigs
  2. Effect of UH on the expression of CRP2, G2COP, MYG, VEGFD,COL4 and FUT4 proteins in porcine embryos
 Discussion
 REFERENCES

• Hye-In Han(College of Animal Life Science, Kangwon National University, Chuncheon 24341, Republic of Korea)
• Sang-Hee Lee(Institute of Animal Resources, Kangwon National University, Chuncheon 24341, Republic of Korea)
• Eun-Ji Song(College of Animal Life Science, Kangwon National University, Chuncheon 24341, Republic of Korea)
• Seunghyung Lee(College of Animal Life Science, Kangwon National University, Chuncheon 24341, Republic of Korea)
• Hee-Tae Cheong(School of Veterinary Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea)
• Boo-Keun Yang(College of Animal Life Science, Kangwon National University, Chuncheon 24341, Republic of Korea)
• Choon-Keun Park(College of Animal Life Science, Kangwon National University, Chuncheon 24341, Republic of Korea) Correspondence