The Mammalian Preimplantation Embryo : Regulation of Growth and Differentiation in Vitro

With a few notable exceptions, mammalian preimplantation embryos grown in vitro are likely to exhibit sub-optimal or retarded development. This may be manifested in different ways, depending on the species and on the stage(s) of embryonic development that are being examined. For example, bovine embryos often experience difficulty in cleaving under in vitro conditions, and usually cease development at about the 8-cell stage (Wright and Bondioli, 1981). The block to development is stage-dependent; embryos cultured for 24 hr from the I-cell stage are much more capable of developing into viable blastocysts after transfer to oviducts than embryos cultured for 24 hr from the 4-cell stage prior to transfer (Eyestone et oZ. , 1985). Similar problems with in vitro embryo development are encountered in other species. Pig embryos can be grown up to the 4-cell stage in vitro but usually no further (Davis and Day, 1978). In the golden hamster, in the rat and in many outbred strains of mice, development of zygotes in vitro is blocked at the 2-cell stage (Yanagimachi and Chang, 1964; Whittingham, 1975). Even with some inbred mouse strains, embryo development is reduced if very early cleavage stages are used as the starting point for in vitro culture (Spielmann et oZ. , 1980). A common finding is that embryos grown in vitro have reduced cell counts (Harlow and Quinn, 1982; Kane, 1985) and their viability is reduced (Bowman and McLaren, 1970; Papaioannou and Ebert, 1986) compared to equivalent developmental stages recovered from mated animals. Front Matter....Pages i-xviii Pioneering Mammalian Embryo Culture....Pages 1-22 Cell Polarity in the Preimplantation Mouse Embryo....Pages 23-41 Intercellular Communication during Mouse Embryogenesis....Pages 43-64 Development of the Blastocyst: Role of Cell Polarity in Cavitation and Cell Differentiation....Pages 65-93 In Vitro Assessment of Blastocyst Differentiation....Pages 95-116 Steroid Hormones in Early Pig Embryo Development....Pages 117-132 Genetic Expression during Early Mouse Development....Pages 133-150 Defining the Roles of Growth Factors during Early Mammalian Development....Pages 151-174 Interaction of Trophoblastic Vesicles with Bovine Embryos Developing in Vitro....Pages 175-191 In Vitro Growth of Preimplantation Rabbit Embryos....Pages 193-217 Studies on the Developmental Blocks in Cultured Hamster Embryos....Pages 219-249 Growth of Domesticated Animal Embryos in Vitro....Pages 251-271 In Vitro Growth of Non-Human Primate Pre- and Peri- Implantation Embryos....Pages 273-308 Analysis of Embryotoxic Effects in Preimplantation Embryos....Pages 309-331 Applications of Animal Embryo Culture Research to Human IVF and Embryo Transfer Programs....Pages 333-340 Back Matter....Pages 341-379