In vitro fertilization and preimplantation development in the primate
Nonhuman primates represent a strong model for examining the chromosomal, biochemical, and temporal normality of embryos produced byin vitro fertilization. Morein vitro fertilized embryos from the squirrel monkey(Saimiri sciureus) have been produced and examined than with all other primate species combined. In studies over a 13 year period a fertilization rate approximating 60 % has been developed in this species with 30% of these embryos proceeding to the two cell stage and 50% of these to the three-four cell stage. Chromosomal abnormalities (primarily missing or extra chromosomes) at a level of nine to 16% have been found, a value corresponding to that found inin vivo mating andin vitro fertilization in other species. An incidence of triploidy of 16.7% was observed. RNA and protein synthetic rates appear comparable with those of laboratory species subjected toin vitro fertilization and indicate the initial stages of metabolic activity of the newly formed embryo. Similarly, increases in estrogen incorporation appear after fertilization but no effect is observed in progesterone incorporation. Utilizing 2-deoxy-glucose and insulin, it was determined that the glucose requirement as an energy source for early preimplantationin vitro fertilized primate embryos is very low.
Of very great importance is the temporal relationship of the development ofin vitro fertilized squirrel monkey embryos compared with similar development in other primates (including humans) afterin vivo andin vitro fertilization. An analysis of over a decade of work with the squirrel monkey embryos demonstrates a pattern of temporal development that is comparable with all other primate species that have been examined (including the human) and comparable with development afterin vivo fertilization.