INCREASED MESSENGER-RNA LEVELS OF TRANSFORMING GROWTH-FACTOR-BETA-1 AND MONOCYTE CHEMOATTRACTANT PROTEIN-1 IN ULCER RELAPSE CAUSED BY INTERLEUKIN-1-BETA IN RATS

This study investigated the mRNA expression of transforming growth fac tor-beta 1 (TGF-beta 1) and monocyte chemoattractant protein-1 (MCP-1) in rat gastric tissues in which ulcers had relapsed due to interleuki n-1 beta (IL-1 beta) administration. Rats with healed ulcers were admi nistered IL-1 beta (1 mu g/kg) and killed after 0, 12, 24, or 48 hr. B oth TGF-beta 1 and MCP-1 mRNA levels were increased in the scarred gas tric tissues at 24 hr (four-fold), when ulcers had not relapsed. Furth ermore, the expression of these genes also increased in the ulcerated gastric tissues at 48 hr (fivefold), when 90% of healed ulcers had rel apsed. On the other hand, the number of macrophages that had infiltrat ed the scarred gastric tissues at 24 hr was two times higher than that at 0 hr. At 48 hr, the number of macrophages that had infiltrated gas tric tissues in which ulcers had relapsed was similar to that at 24 hr . Thus, TGF-beta 1 and MCP-1 may be implicated in the macrophage infil tration, thereby leading to ulcer relapse due to IL-1 beta.