Pathogenesis of the mucosal hyperplasia in self-filling blind loops of rat jejunum: a morphometric study in germ free animals.

Bacterial overgrowth and high intraluminal concentrations of deconjugated bile acids are thought to be responsible for mucosal hyperplasia in self-filling blind loops of rat jejunum. To investigate this hypothesis further we have assessed the three dimensional architecture of these loops created in germ free animals without or with di- or mono-association of different bacterial species. It was found that mucosal hyperplasia develops in the absence of any bacterial contamination and that bacterial association does not lead to a more pronounced mucosal proliferation. This implies that other mechanisms provoke this morphological phenomenon. Increased bulk contents in these loops or immunological events are probably the most likely explanation.