Separation and culture of ovine endometrial epithelial and stromal cells: evidence of morphological and functional polarity.

Epithelial and stromal cells from endometria of ovariectomized estradiol-treated Corriedale ewes were separated and purified after collagenase digestion. The separation method utilized differences in the speed and ease of detachment of cultured epithelial and stromal cells attached to plastic in response to brief trypsin exposure. Cells were characterized according to morphological, growth, and histochemical criteria. Contamination of each cell type with the other was less than 1%. Separated cells were grown on plastic or on Matrigel-coated Millicell inserts with nitrocellulose membranes. Transmission and scanning electron microscope analyses demonstrated the existence of tight junctions and prominent microvilli in the epithelial cultures on inserts but not on plastic. Asymmetrical secretion of prostaglandin F2 alpha (PGF2 alpha) and prostaglandin E (PGE) by epithelial cells provided further evidence of polarization. Epithelial cell secretion of PGF2 alpha was greater than that by stromal cells whereas PGE secretion by stromal cells was greater than that by epithelial cells. Epithelial secretion in the basal direction was approximately 4 and 3 times that of apical secretion for PGF2 alpha and PGE, respectively. The separation protocol provides pure populations of ovine endometrial epithelial and stromal cells and the cultured epithelial cells exhibit characteristics of in vivo morphology and polarized function.