[The study of the developmental potential of early embryonic cells of rabbit]

The developmental potential of rabbit embryonic cells was studied through making chimera by separate introduction of inner cell mass from 96-h-old p. c., 120-h-old p. c., and 144-h-old p. c. of grey rabbits into 96-h-old p. c. blastocysts of New Zealand white rabbits. A total of five overt chimeras were obtained including two fertile males, two fertile females and one sterile male, from the ICM cells of 96-h-old and 120-h-old embryos but none was obtained from 144-h-old cells. Histological examination of the gonad showed that the sterile chimera derived from 120-h-old ICM cells with an ovotestis on both sides. Follicles and seminiferous tubules developed in the cortex and medulla of the gonad, respectively. Neither of them developed into functional germ cells. Analysis of karyotypes of peripheral blood showed that both XX and XY coexisted in lymphocytes. These results indicated that the sterile male chimera was a XX/XY sex chimera derived from ICM cells of donor and recipients with different sex, so as to the chimera with XX and XY genotypic cells. From the results mentioned above we may conclude that the ICM cells at 120-h-old p. c. are still pluripotential, they can not only participate in development into somatic components but also develop into germ cells. The potential of 144-h-old p. c. ICM cells seems to be rather restricted.