Development of Transplanted Rat Eggs

Abstract

The first experiments employing transplantation of mammalian eggs were reported by Heape more than 40 years ago. He transferred the eggs of an Angora rabbit into the uterus of the Belgian hare. Similar work is reported by Hammond. As a part of the program of work on the development of the rat, this experiment has been repeated as a test for egg viability and its capacity for continued development. The transplantations were performed between white and hooded rats in order that the pigmentation could be used as a decisive criterion of the original maternal origin of the developing eggs. Since pigmentation develops at the close of the first half of pregnancy, it is not necessary to carry the young completely through the gestation period to study the survival of the transplanted eggs. The animals are mated and the Fallopian tube of one side is removed from both the donor and the recipient females at the desired interval after fertilization; the eggs are secured from the Fallopian tube and the donor's eggs (hooded) are transferred to the recipient's (white) uterus. The effects of the operative procedure have been tested and the results show that one horn of the uterus can be removed without disturbing the development of the embryos contained within the opposite horn. The horn of the uterus can be transferred to a subcutaneous environment without interfering with the development of the subsequent litter. Further tests were made under the conditions peculiar to the present experiment and the Fallopian tube of one side was removed at the close of the third day of the gestation period. The young develop in the horn of the side of operation and were born alive in nearly 90% of the cases (13 litters out of 15) with no change in the length of the gestation period.