Morphological characteristics of human endometrial epithelial cells cultured on rat-tail collagen matrix

Epithelial cells were isolated from normal human endometrium and cultured on reconstituted matrices of rat-tail collagen gels. Cells attached within 24 h after plating. Initially, epithelial cells were not structurally polarized, had projections from both apical and basal domains and were generally flat to cuboidal in shape. When the gels were made free floating 36-48 h after initiation of the cultures, the epithelial cells became columnar in shape as the gels underwent contraction. Although a maintained growth profile was observed during the 10 days of culture, there was a linear decrease in gel matrix diameter along with increasing loss of transparency. Electron microscopy revealed the presence of apical microvilli, junctional complexes, lipid droplets and endoplasmic reticulum in cultured epithelial cells. The basolateral dilatations and lateral membrane plications were seen in these cells by 6-8 days in culture. With gel contraction, rearrangement of matrix material was observed. Occasionally there were basal lamina-like structures adjacent to the flattened basal surface and the formation of gland-like structures within the matrix. The three-dimensional primary culture of human epithelial cells on collagenous biomatrix appears to be a potential experimental tool for the study of cell-cell and cell-matrix interactions, and of the study of the effects of endocrine and paracrine factors on these cells in vitro.