B. Kramer et al., HYPERSTIMULATION AFFECTS VASCULAR-PERMEABILITY AT IMPLANTATION SITES IN THE RAT ENDOMETRIUM, Journal of assisted reproduction and genetics, 10(2), 1993, pp. 163-168
Purpose: It has previously been shown that deleterious changes occur i
n the epithelium and stroma of the endometrium of the rat following ov
arian hyperstimulation by exogenous gonadotropins. The purpose of the
present study was to investigate the formation of possible implantatio
n sites following hyperstimulation. Female rats (n = 8) were injected
in phase with their estrous cycle with follicle stimulating hormone (F
SH), followed by human chorionic gonadotropin (hCG), and mated at proe
strous. Control rats (n = 6) were uninjected and mated at proestrous.
Animals were killed at 5.5 days of pregnancy. The pontamine blue techn
ique was used to demonstrate the permeability of the uterine vessels.
Implantation sites were demonstrated in the uterine horns of all contr
ol animals by segmental blue banding. Results: Blue staining occurred
only in a portion of one horn of one hyperstimulated animal. While fen
estrations were found in the walls of capillaries of control animals,
similar fenestrations were not observed in the vessels of hyperstimula
ted animals. Conclusion: As the walls of vessels in the hyperstimulate
d animals failed to become permeable, and as no implanting embryos wer
e found in these animals, it is concluded that there was an inability
of the endometrium to form implantation sites. These changes may imped
e attachment and implantation of the embryo.