Intestinal metaplasia as a common option of oval cells in relation to cholangiofibrosis in liver of rats exposed to 2-acetylaminofluorene.

Oval cell proliferation in the liver was studied in rats exposed to dietary 2-acetylaminofluorene for 2 weeks with partial hepatectomy performed midway at 1 week. Using autoradiography after either continuous or pulse exposure to [3H]thymidine, histochemical staining for leucine aminopeptidase and gamma-glutamyltransferase, and transmission electron microscopy, we found that every animal showed islands of oval cells with small intestinal metaplasia at 3 weeks. Transitions from these islands of metaplasia to cholangiofibrosis were commonly seen. The importance of small intestinal metaplasia of oval cells in the genesis of cholangiofibrosis is presented and discussed.