ABSTRACT
Culture requirements for in vitro development of human preimplantation embryos have not been fully defined. Helper cells in coculture would pave the way for repro-ducible embryo culture system of in vitro fertilization-embryo transfer(IVF-ET) in human. The purpose of this study is to evaluate the influence of BRL cells in coculture on human embryo development in vitro. Supernumerary 2-8 cell stage embryos from IVF-ET patients were used in this experiment. The embryos were assigned to two treatments, one for conventional embryo culture in 2 ml of Ham's F10 + 15% huamn serum(control), and the other for the coculture trial. Monlayer for the coculture of embryos was prepared by plating 1X 10(5) viable BRL cells per well in 4-well tissue culture plate 48 hours prior to the onset of coculture. In twenty four hours after plating, all wells were washed out and 0.5 ml of the medium was placed into the well and then preincubated. Embryos were scored according to embryo quality, assigned to each treatment and further cultured for 5 days. A total of 63 embryos from 10 patients were randomized(23 controls, 40 coculure). With grade I embryos, higher percentage of embryos in coculture group developed to blastocyst stage(61.3%) than in control group(30.7%, p < 0.05). With grade II and III embryos, no differences in the rates of development to morula and blastocyst sta-ge were found between control and coculture groups. The overall rates of development to morula and blastocyst stage were 65.2% and 21.7%, 77.5% and 50.0% for control and coculture, respectively. Differences in the development to blastocyst stage were found between control and coculture groups(p < 0.05). The data indicate that BRL cell coculture improves human embryo development to balstocyst stage in vitro.