Fibroblast growth factor 21 ameliorates pancreatic fibrogenesis via regulating polarization of macrophages.

Chronic pancreatitis (CP) is a progressive, irreversible inflammatory and fibrotic disease. The characteristics of this disease are progressive inflammation, acinar atrophy and fibrosis. Numerous factors are involved in CP such as inflammation, and oxidative stress. Recently, it has been noted that fibroblast growth factor 21 (FGF-21) reduced the severity of acute pancreatitis in mice. However, whether FGF-21 has effects on CP remains unclear. Thus, the present study was undertaken to detect the effects of FGF-21 on l-arginine induced chronic pancreatitis/islet fibrosis in mice. We used l-arginine to create a CP model in C57BL/6 mice and treated these mice with FGF-21. Compared to normal mice, blood glucose and intra-peritoneal glucose tolerance test (IPGTT) revealed significant impairment in CP animal model. CP mice also had acinar atrophy, loss of pancreas morphology, inflammatory cells infiltration, extensive deposition of collagen, elevated -SMA expression, collagen I expression, serum amylase activity, MPO activity and MDA level. All these pathological changes were significantly improved by FGF-21 treatment. Moreover, FGF-21 ameliorated inflammatory state in the serum, pancreas and peritoneal macrophages of CP mice. Furthermore, we also found that FGF-21 could regulate differentiation of macrophages so as to improve pancreatic fibrogenesis in CP mice. Taken together, our study identifies the beneficial role of FGF-21 in CP and suggests that FGF-21 improves pancreatic fibrogenesis in CP via the mTOR pathway.