Primary epithelial cell cultures derived from canine prostate: isolation, culture, and characterization.

Epithelial-cell-enriched primary cultures were established from canine prostate. Minced tissue was dissociated with 750 units/ml of collagenase in F12K tissue culture medium containing 1% fetal bovine serum. This treatment resulted in the gradual removal of stromal elements from the base of the epithelial cells. After 30 minutes of digestion, aggregates of epithelial cells free of stroma were dislodged from the minced pieces of prostate. These aggregates were washed and plated at high density in F12K plus 10% fetal bovine serum. After 12-16 hours in vitro the unattached cellular aggregates were removed from the culture dishes, washed, and reinoculated into new culture vessels containing fresh medium. After 48 hours in vitro, the aggregates had attached to the culture vessels and spread out to yield discrete patches of epithelial cells. By 120 hours in vitro the patches of cells had grown and coalesced to form a confluent monolayer of epithelial cells. Ultrastructural examination of these cultures indicated that adjacent cells were joined by desmosomes and tight junctions and had tonofilaments and microvilli, giving the cells an epithelial appearance. The cells contained rough endoplasmic reticulum, Golgi apparatus, and secretory granules similar to those of the epithelial cells in the intact organ. In addition, intracellular "blebs" containing acid phosphatase were observed in the monolayers and were found to increase in size and number with time in vitro. Differentiated function of the cultures was demonstrated by the presence of ornithine decarboxylase and acid phosphatase and the ability of the cultures to metabolize testosterone to primarily 5 alpha-reduced metabolites.