Histological changes in the endometrial arterioles during postpartum offthe Chinese hamster (Cricetulus griceus)

The morphology of the uterine wall in the postpartum Chinese hamster (Cricetulus griceus) was studied with particular reference to the changes in the arterioles in the mesometrial endometrium. At day 0 postpartum, the endometrial arterioles were characterized by the appearance of trophoblastic giant cells plugging ruptured arterioles. On days 1 to 3 postpartum, the giant cells were replaced by epitheloid cells. On days 4 to 5 postpartum, the epitheloid cell mass was invaded by fibroblasts to occlude the arterial lumens. On days 6 to 7 postpartum, endometrial regeneration was completed. The giant cell might play a role in hemostasis immediately after parturition.