In vitro production of canine blastocysts

Though blastocyst production in vitro has been successful in several animal species, a culture system to produce viable and normal canine blastocysts in vitro remains to be established. In this study, we report the development of an in vitro culture system for canine preimplantation embryos produced via parthenogenetic activation (PA) and somatic cell nucleus transfer (SCNT). Our results show that the medium developed by us, named "Qingdao Agricultural University's (QAU)-4 medium", successfully breaks the developmental arrest observed at the eight-cell stage in canine embryos grown in other culture systems. The blastocysts produced in QAU-4 displayed normal blastocyst structures, including a clear inner cell mass and blastocyst cavity. We also found that blastocyst formation in PA embryos cultured in QAU-4 medium was quite high, though this was not so in the case of SCNT embryos. However, supplementation of QAU-4 medium with 100 nM of scriptaid caused a sharp increase in blastocyst formation in SCNT embryos. After culture, hatched blastocysts were also observed to successfully adhere to collagen-coated dishes, where further growth and differentiation occurred. To our knowledge, this is the first in vitro canine preimplantation embryo culture system that can successfully produce canine blastocysts.