Overexpression of Redox-Active Protein Thioredoxin-1 Prevents Development of Chronic Pancreatitis in Mice

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-β, 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 H₂O₂-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.