[A morphological study of glandular formation and epithelialization from normal human endometrial epithelial cells in...

We employed basement membrane extracts (BME) prepared from Engelbreth-Holm-Swarm tumor for in vitro culture of normal human endometrial cells (E-cells) and observed a process of glandular formation followed by epithelialization. E-cells isolated enzymatically were cultured in BME-coated culture dishes and morphological observations were carried out. The results were as follows: 1) E-cells cultured on BME had a globular shape, grew in a helix-like pattern, and formed a tubular glandular structure, rising perpendicularly above the BME surface. 2) Following the glandular formation, 2 weeks after the beginning of the culture, E-cells on the top of the glandular structure spread out in all directions and formed an epithelial-like monolayer cell sheet on the surface of the BME mimicking superficial luminal epithelialization. 3) Glandular E-cells were columnar in shape, had numerous surface microvilli, and faced a lumen which was sealed by a tight junction complex of cells. Superficial E-cells were cuboidal in shape, with mild polarized organelles, nuclei, and abundant microvilli and the surface was entirely covered with BME. These results indicated that this culture system using a BME could be useful in studying the physiology of the human endometrium in vitro and the mechanism of reproduction.