Transplantations of Tissues in Fetal Rats.

Abstract

Transplantations have been used in order to determine the amount of differentiation which may take place in fetal mammalian structures and also to study the changes which may occur in such tissues following their transplantation to strange environments.

The method of procedure in operations upon the mammalian fetus has been described previously. 1 It is necessary to use fetuses of the earliest possible stage of development in order to secure the tissues in the least differentiated stages. This is difficult in the albino rat fetus because of the absence of anatomical landmarks which will assist the operator in localizing the tissue which it is desired to remove from the embryo. In order to secure an anatomical landmark a cross was made between albino and hooded stock. This cross gave both albino and hooded fetuses in the same litter, oft-times within the same uterine horn. Pigment develops in the eye of the hooded rat at about the tenth day of gestation age. Unless some factor is used for orientation so much handling is necessary that the damage to the tissues precludes any chance of a successful experiment.

Two series of transplantations were performed: (1) transplantations of the globus oculi and (2) transplantations of the forelimb.

The globus oculi was removed from one animal of a litter and transplanted to various regions of a second fetus. A pigmented globus was used as the graft, the host being albino. In this way an accurate check and a simple method of localizing the transplant in the host were obtained. The eye was transplanted under the skin over the abdomen, within the abdominal cavity and under the skin of the thorax. Of these locations, the flank over the abdomen gave the greatest number of successful cases, the abdominal cavity next and the thoracic subcutaneous region the lowest.