Chronic pancreatitis (CP) is considered to result from repetitive pancreatic injury, and sustained production of various proinflammatory cytokines and chemokines are closely involved in its pathogenesis. Monocyte chemoattractant protein 1 (MCP-1), a member of the CC chemokine family, is believed to contribute to the progression of CP through monocyte/macrophage recruitment. This study aimed to clarify the protective role of thioredoxin-1 (TRX-1), a redox-regulating protein with antioxidative activity, in MCP-1 production and pancreatic fibrosis using a CP model in transgenic mice overexpressing TRX-1 (TRX-1-TG mice) and wildtype C57BL/6 mice. Experimental CP was induced by repeated administration of cerulein and lipopolysaccharide for 6 weeks. In TRX-1-TG mice, pancreatic atrophy was ameliorated, and histologically detectable inflammatory cell infiltration, glandular atrophy, and pseudotubular complex formation were suppressed. Overexpression of TRX-1 also attenuated pancreatic fibrosis and suppressed the activation of pancreatic stellate cells. Serum levels of MCP-1 and pancreatic expression of transforming growth factor-beta, platelet-derived growth factor, and MCP-1 were reduced in TRX-1-TG mice compared with levels in wild-type mice. Overexpression of TRX-1 also reduced H(2)O(2)-induced MCP-1 production in isolated pancreatic acinar cells. These results indicate that TRX-1 can potentially attenuate pancreatic fibrosis via the suppression of oxidative stress and MCP-1-mediated chronic inflammation.