CHARACTERIZATION OF A POLARIZED PORCINE UTERINE EPITHELIAL MODEL SYSTEM

A porcine uterine epithelial cell (pUE) culture system that retains st ructural and functional properties of the surface epithelium in vivo w as developed. Uterine luminal epithelial cells were isolated after pan creatin-dispase enzymatic release of epithelium from hysterectomized g ilts. Cells were seeded on Millicell filters precoated with Matrigel i n 24-well plates and subsequently allowed to proliferate to confluence . Purity of the isolation was confirmed by the presence of > 99% cytok eratin-positive cells. Epithelial cells became polarized in vitro and compared favorably in morphology to uterine epithelial cells in situ o nce a transepithelial resistance of > 600 Omega cm(2) was established. Microscopic analysis confirmed the presence of a simple columnar epit helium with prominent microvilli on the apical cell surface and a well -developed junctional complex containing tight junctions, belt and spo t desmosomes, and interdigitating lateral cell processes. Indirect imm unofluorescence of the tight junction-associated protein, ZO-1, indica ted the formation of tight junctional complexes in the subapical regio n of the polarized cells. Functional polarity of epithelial cultures w as also verified by 1) electrical resistance measurements, 2) basal pr eference for the secretion of prostaglandins F-2 alpha and E(2), 3) ap ical preference for the release of S-35-methionine-incorporated secret ory proteins, and 4) apically and basally distinct secretory protein p rofiles. Steroid treatment (estrogen, progesterone, or estrogen plus p rogesterone) of the polarized pUE cells affected the release of radiol abeled methionine-incorporated secretory proteins. In addition, the pr otein profiles as compared to samples treated with fetal bovine serum or charcoal/dextran-stripped fetal bovine serum were altered. Steroid treatments did not alter the electrical resistance or the basal prefer ence for prostaglandin secretion. This culture system may be useful fo r in vitro analysis of maternal recognition of pregnancy paradigms as well as the study of the direct actions of hormones, prostaglandin sec retion, and epithelial-stromal interactions.