Changes in Fertility and Morphology of Sensitized Rat Uterine Endometrium upon an Intra-uterine Injection of Antigen

Abstract

Rats were immunized with BCG-vaccine or horse serum and divided into two subgroups, one containing pregnant animals, the other containing spayed animals treated with progesterone. The pregnant rats were given an intra-uterine injection of the antigen on day 3 of pregnancy and the number of foetuses was registered. The spayed rats were first given progesterone, then an intrauterine injection of the antigen, and prepared for microscopy at various intervals. The results showed that an intra-uterine injection of BCG-vaccine rendered implantation impossible and also markedly changed the structure of the endometrium. Serum, in the corresponding experiments, did not block implantation, but morphological signs of an immune reaction were present although not in the uterine epithelium. It is concluded that with the design used, an immunological reaction of the immediate-type cannot change the structure and function of the uterine epithelium sufficiently to render implantation impossible.