Acute epithelial injury in the rat small intestine in vivo is associated with expanded expression of transforming growth factor alpha and beta.

Abstract

Previous studies have shown the importance of transforming growth factors alpha and beta (TGF alpha and TGF beta) in modulating epithelial cell restitution after injury in vitro. To investigate the role of the growth factors TGF alpha and TGF beta after acute epithelial injury in vivo. An in vivo model of phytohaemagglutinin (PHA) induced acute epithelial injury in rat small intestine was used. Epithelial cell turnover was assessed by autoradiography and liquid scintillation counting of thymidine uptake. Expression of TGF alpha and TGF beta was assessed by immunohistochemistry. An expansion of the proliferative compartment and increased turnover of intestinal epithelial cells was seen in rats with PHA induced intestinal epithelial injury. Expression of TGF alpha and TGF beta peptides was shown in both the epithelial cell and lamina propria compartment. Different patterns of TGF alpha and TGF beta expression were seen, however, within the epithelium of rats with acute intestinal injury compared with untreated controls, while the expression of these peptides within the lamina propria was not changed. These findings suggest that acute intestinal epithelial cell injury in vivo is associated with compensatory changes in expression of TGF alpha and TGF beta in the epithelial cell compartment, while the lamina propria does not seem to be significantly affected.