Chun Yang Wen

Mechanism of the antiulcerogenic effect of IL-11 on acetic acid-induced gastric ulcer in rats

The purpose of this study was to evaluate the healing effect of interleukin-11 (IL-11) on acetic acid-induced gastric ulcer in rats. Gastric ulcers were induced in male Wistar rats by applying acetic acid to the fundus of the stomach. Recombinant human interleukin-11 (rhIL-11 100 microg/kg/twice daily, subcutaneously) was administered starting on the 2nd day before ulcer induction up through the 7th day after ulcer induction. Control rats were injected with bovine serum albumin. At 12 hours and 7 days after ulcer induction, the animals were sacrificed, and the ulcer index, proliferating cell nuclear antigen (PCNA) expression, and IL-11alpha receptor expression in the gastric tissues were studied. The ulcer index of the rhIL-11-treated rats was significantly lower than that of the control rats at the 7th day. The expression of PCNA as evaluated by Western blotting and immunohistochemistry, was enhanced in both the mucosal proliferative zone and proper muscle layer of the rhIL-11-treated rats in comparison with that in the control rats. IL-11alpha receptor expression was observed in the mucosal neck cells of the rhIL-11-treated rats and control rats. These findings suggest that IL-11 accelerates ulcer healing by inducing the proliferation of mucosal and muscular cells.

Expression of Tie-2 and angiopoietin-1 and -2 in early phase of ulcer healing

Background. Angiogenesis is an important process in tissue development and wound healing. The Tie-2 receptor tyrosine kinases and ligands, angiopoietin (Ang)-1 and -2 have been postulated to play key roles in vascular development. The purpose of this study was to evaluate the expression of Tie-2 and Ang-1 and -2 in an acetic acid-induced gastric ulcer healing process in rats. Methods. Gastric specimens were obtained at 0 (control), 1, 3, 5, 7, and 14 days after ulcer induction for reverse transcription polymerase chain reaction (RT-PCR), Western blot analysis, and immunohistochemical analysis. Results. Expression of Tie-2 and Ang-1 and -2 mRNAs was detected in normal gastric tissue and ulcerative tissues by RT-PCR. Western blot analysis revealed that Tie-2 expression reached a maximum on the third to fifth days. Expression of Ang-1 and -2 peaked on the first day. Ang-1 expression gradually became weaker in 2 weeks, whereas Ang-2 expression returned to normal in a few days. Immunohistochemically, Tie-2 was expressed constitutively in the endothelial cells of pre-existing vessels of the gastric wall, and Tie-2 expression was increased in the new capillaries of the ulcer base. Conclusions. These findings suggest that Tie-2 and Ang-1 and -2 play an important role in angiogenesis in the early phase of ulcer healing.