Expression of decorin and biglycan in rat gastric tissue: Effects of ulceration and basic fibroblast growth factor

Background: The small chondroitin/dermatan sulphate proteoglycans decorin a nd biglycan participate in organizing the network of collagen fibrils and i nteract with non-collagenous matrix proteins. In addition, via interactions with cytokines they are directly or indirectly involved in signalling, gro wth and cell differentiation. We aimed to analyse their expression in norma l gastric tissue and during gastric ulcer healing. Methods: Proteoglycan ex pression was studied by immunohistochemistry and in situ hybridization in a cetic acid-induced gastric ulcers in rat during early phases and during chr onic ulceration. The effects: of treatment with an acid stable mutein of FG F-2 (bFGF) were also studied. Results: In normal gastric tissue, both prote oglycans were most strongly expressed in the submucosal layer. However, som e epithelial cells were positive for biglycan and, surprisingly, also for d ecorin. In the early phase after ulcer induction exclusively decorin became induced in the muscularis mucosae, while biglycan became detectable in thi s layer only after 2 weeks. There was no up-regulation of either proteoglyc an in other layers. nor could an effect of FGF-2 treatment be seen. Conclus ions: The expression of decorin could be observed for the first time in epi thelial cells. Decorin, but not biglycan, appears as an early phase reactan t in the muscularis mucosae in accordance with its putative role during ang iogenesis and the prevention of apoptosis.