Histological and ultrastructural regulation in rabbit endometrial explants by estrogen in serum-free culture

A repertoire of hormonal signals including estrogen regulate the growth, differentiation, and functioning of diverse target tissues, including the ovary, the mammary gland, and skeletal tissue. A serum-free culture system derived from rabbit endometrium explants has been devised and is reported here to explore estrogen action in vitro. The system involves aseptically harvesting the uterus from a virgin rabbit, dissecting the endometrium, explanting it into 1- to 2-mm(3) pieces weighing approximately 1-2 mg each, and incubating these pieces in serum-free Medium-199. The culture is carried out for a period of 4 d in a humidified CO(2) incubator at 37 degrees C with 5% CO(2). The effect of extraneously added estrogen (1 microg/ml) was investigated by histological and ultrastructural procedures. It was observed that estrogen could induce specific changes, such as abundant mitochondria, rough endoplasmic reticulum, golgi complex, and intracellular collagen deposition, in both the epithelial and the fibroblast cell components of the explanted tissue. The study, therefore, indicates that the proposed system is an ideal tool for exploring and demonstrating estrogen responsiveness under in vitro conditions.