Expression of fibroblast growth factor-2 transcripts in the healing of acetic acid-induced gastric ulcers

Basic fibroblast growth factor-2 (FGF-2) has an important role in angiogenesis, and has been demonstrated to promote ulcer healing. However, the actual part played by FGF-2 in the process of ulcer healing is not well understood. In this study, we investigated expression of FGF-2 transcripts at each stage of gastric ulcer healing, using an acetic acid model in rats. We made ulcers in the rat stomach by direct application of acetic acid, and 3 days and 1, 2, 3, 4, 8 weeks after treatment, we examined expression of FGF-2 transcripts by in situ hybridization. On day 3, FGF-2 transcripts were detected in mononuclear cells infiltrating the submucosal layer around the ulcer. After 1 and 2 weeks, expression of FGF-2 transcripts was prominent in spindle-shaped mesenchymal cells and endothelial cells, which proliferated in the ulcerative region. Some of the spindle-shaped cells which expressed FGF-2 transcripts also showed immunoreactivity for a-smooth muscle actin. After 3 and 4 weeks, FGF-2 expression was seen mainly in endothelial cells of vessels. These results suggest that different cells produce FGF-2 during the process of gastric ulcer healing, and some of the spindle-shaped cells expressing FGF-2 transcripts in the early phase are myofibroblasts.