Characterization of the rabbit gastric epithelial lineage progenitors in short-term culture

Little is known about the mechanisms that establish and maintain the prolif eration and differentiation programs of the gastric epithelium. This is lar gely due to the complexity of the gastric epithelial units and the presence of the different epithelial lineage progenitors among heterogeneous popula tions of various mature cell types. This study is undertaken to establish a n in vitro system highly enriched for gastric epithelial lineage progenitor s. By using adult male rabbits, a simple method of isolating gastric epithe lial cell fractions enriched in lineage progenitors was applied. Cultured c ells labeled with bromodeoxyuridine were characterized by using lectin and immunohistochemical studies at light- and electron-microscopical levels. An alysis of primary cultures derived from the progenitor cell region of the e pithelial units revealed that this system can support the proliferation and some of the differentiation programs of the progenitor cells. Cultured cel ls can be maintained for up to 5 days, while retaining most of the morpholo gical features, molecular markers, and dynamic behavior of gastric epitheli al progenitors. Differential cell counts at 1-day culture revealed that, wh ile the undifferentiated progenitors formed about 30% of all attached cells , pre-pit, pit, and preparietal cells represented about 30%, 10%, and 2%, r espectively. By 3 days, the increase in the percentage of pit and prepariet al cells up to 25% and 9%, respectively, reflected their production in vitr o. In conclusion, we have established a culture system enriched for gastric epithelial lineage progenitors that would hopefully allow the identificati on of factors and mechanisms involved in controlling their proliferative ac tivity and differentiation pathways.