PP9 - Docosahexaenoic acid inhibits oxidative stress and cytokine expression in pancreatic stellate cells exposed to double-stranded RNA or TNF-alpha

Abstract

Activated pancreatic stellate cells (PSC) play a pivotal role in the pathogenesis of pancreatic fibrosis and inflammation. Reactive oxygen species (ROS) levels are increased in the serum of the patients with pancreatitis. ROS mediates expression of inflammatory cytokines in various tissues. Docosahexaenoic acid (DHA), omega 3-polyunsaturated fatty acid, shows anti-inflammatory effects in inflammatory diseases. In the present study, we investigated whether DHA inhibited ROS production and cytokine expression in PSC exposed to double-stranded RNA (Poly (I:C)), as a model of viral infection, or TNF-alpha. PSC were isolated from rats and treated with poly (I:C) or TNF-alpha in the presence or absence of DHA. mRNA expressions of MCP-1 and CX3CL1 were assessed using real-time PCR. DCFDA (2’,7’ –dichlorofluorescin diacetate), MitoSox red and JC-1(5,5’,6,6’-tetrachloro-1,1’,3,3’-tetraethylbenzimidazoylcarbocyanine iodide) were used to determine intracellular ROS production, mitochondrial ROS production, and mitochondrial membrane potential (MMP), respectively. As a result, TNF-alpha and Poly (I:C) induced increases in intracellular and mitochondrial ROS as well as expression of MCP-1 and CX3CL1, but reduced MMP in PSC. DHA inhibited intracellular and mitochondrial levels of ROS, disruption of MMP, and cytokine expression in PSC treated with Poly (I:C) or TNF-alpha. In conclusion, supplementation of DHA may be beneficial for preventing pancreatic inflammation/fibrosis by inhibiting cytokine expression in PSC.