An ultrastructural and biochemical analysis of the epithelial-mesenchymal interface of the ruminal mucosa during development.

The ultrastructure of fetal and adult bovine epithelial-mesenchymal interface of the ruminal mucosa was described and then correlated to the biochemical analysis for glycosaminoglycans (GAGs). During development a progressive undulation of the basement membrane, increase of connective tissue filamentous material, and folding of the cellular membrane of the basal epithelial cells were observed. Coincidently, a decrease in the relative composition of hyaluronic acid and an increase in chondroitin sulfate was observed. These results suggest a correlation between glycosaminoglycans composition and the expression of some cellular events resulting in morphological changes which operate during ruminal morphogenesis.