Prevention of Delayed Implantation in Rats by Means of an Intrauterine Foreign Body

Abstract

Summary. The presence of a foreign body in the uterine horn prevented implantation in rats when the process was delayed experimentally for 6 days. The contralateral horn, however, showed normal implantations. Colony-bred mature female rats weighing 120 to 130 g were used in this study. They were maintained under uniform laboratory conditions throughout the ex¬ perimental period. A surgical silk suture was inserted through the antimeso¬ metrial wall of the right uterine horn by an atraumatic needle under ether anaesthesia. The needle with the suture was passed along the uterine lumen and brought out through the same wall approximately 1 -2 to 1 -5 cm above the point of insertion. The suture was pulled loosely through the site of entry so that it lay freely in the uterine lumen. The two ends of the suture were tied into a knot, permitting free movement of the uterus. The needle was passed through the left uterine horn in the same way, but was then withdrawn; this horn served as the control. The operations were performed under aseptic conditions. The animals were put with males 60 days after insertion of the suture. The day on which a vaginal smear contained spermatozoa was considered Day 1 of pregnancy. The method of Cochrane 8c Meyer (1957) was used to induce implantation by oestrogen injection after a delay period of 6 days imposed by progesterone treatment. 139

The Effect of an Intra-Uterine Suture on Fertility in the Rat

“…This is in contrast with the finding of Doyle & Margolis (1963, 1965, Kar et al (1964) and Marston & Chang (1965), who found that the thread completely prevents implantation. Hence differences in methods must be considered.…”

“…Greenwald used attached threads passing for 5 mm through the tissue of the horn. The length of the threads in our own experiments was 5 to 8 mm and thus differs only from those used by Kar et al (1964). Only threads passing through the lumen prevent implantation according to Greenwald. In our experiments it could be shown that even such threads do not always prevent implantation.…”

“…The length of the thread passing through the lumen might also play a role. This length was 5 to 8 mm in the experiments of Doyle & Margolis and 12 to 15 mm in those of Kar et al (1964). Greenwald used attached threads passing for 5 mm through the tissue of the horn.…”

“…Different types of sutures had different effects. In rats, silk sutures completely prevent implantation (Doyle & Margolis, 1963, 1965 Margolis Kar, Kamboj & Datta, 1964; Kar, Kamboj, Goswami & Chowdhury, 1965). Greenwald (1965), however, found that in some rats implantation does occur in the horns with sutures.…”

The Effect of an Iufb on Reproduction in Mice

“…Results from investigations in rabbits (Carleton & Phelps, 1933;Eckstein & Adams, 1964), rats (Doyle & Margolis, 1963;Kar, Kamboj & Datta, 1964;Chaudhury, 1964;, rumi¬ nants (Hawk, Conley, Brinsfield & Righter, 1964), and monkeys (Mastroianni & Hongsonand, 1964) have shown that although an iufb is effective in varying degrees in all these species, the time and mode of action differ. The animals studied thus far, however, also differ widely in one or more aspects of their reproductive anatomy and/or physiology.…”