Effect of loss of mechanical distension on collagen degradation in the mouse uterus.

In unilaterally pregnant mice, loss of mechanical distension induced by artificial removal of fetuses from the pregnant uterus was followed by oedema in the endometrium. No endometrial oedema was found in the non-pregnant uterine horn, which did not experience the loss of mechanical distension at parturition. Ovariectomy on the last day of pregnancy did not prevent the appearance of endometrial oedema on the day of parturition. These histological results indicate that collagen degradation following the loss of mechanical distension of the uterine wall is attributable to formation of oedema in the endometrium.