Regeneration of small intestinal mucosa after acute ischemia-reperfusion injury.

To determine whether c-Fos and c-Jun are involved in the repair of small intestinal mucosa after ischemia-reperfusion (I/R), we investigated the mechanism of regeneration following acute I/R injury in rats by evaluating changes in DNA synthesis, fractional synthesis rate (FSR) of proteins, and alkaline phosphatase (ALP) activity. Furthermore, we examined the sequential expression of c-Fos and c-Jun using western blot analysis and immunohistochemical staining. Proliferating cell nuclear antigen (PCNA) labeling index (LI) demonstrated that the LI of the I/R group at 2 and 6 hr after reperfusion was significantly higher than that of the controls. Statistically significant differences were found between the FSRs of the I/R group and the corresponding conventional group at 2, 6, and 12 hr. The expression of c-Fos and c-Jun proteins increased markedly after I/R and these proteins decreased with time. The levels of ALP in the I/R group were significantly decreased at 2 and 6 hr after reperfusion compared to controls. These results indicate that c-Fos and c-Jun play a central role in the repair process that results in complete restoration of intestinal mucosal function after I/R.