Protective Effects of Paeonol on the DSS-Induced Colitis in Rats

Paeonol was separated from a Paeonia species, which is a traditional Chinese medicine and has been revealed analgesic and anti-inflammatory effects. Inflammatory bowel disease (IBD) is characterized by recurrent episodes of colonic inflammation and tissue degeneration. The present study aims to explore whether paeonol produces protective effects on DSS (dextran sulfate sodium)-induced colitis and its possible mechanisms. Intraperitoneal paeonol significantly attenuated disease activity index (DAI), maintained the ultrastructure of intestinal and reduced VEGF production in a dose-dependent manner. On day 10, the concentration of IL-2, IL-4, IL-10 and TNF alpha in serum, and myeloperoxidase (MPO) activity in colon tissue were assayed using ELISA Kits after mice sacrificed. The mRNA levels of a series of proinflammatory factors including IL-2, IL-4, IFN-gamma, IL-10, IL-17 in colon tissue were measured by real time PCR. The increase in IL-2, IL-4, IL-10, and TNF alpha in serum and MPO activity induced by DSS was significantly reversed by paeonol (30 mg/kg, i.p.). Meanwhile, Using real time PCR and Immunohisto-chemistry, paeonol (30 mg/kg) decrease the mRNA level of RORc and Foxp1 to inhibit differentiation of T cells into Th1 or Th2 cell fates. Paeonol (30 mg/kg, i.p.) also decreased the phosphorylation levels of p38 and NF-kappa B p65 which were unregulated by DSS. However, there were no marked changes between expressions of total p38 and NF-kappa B p65. Taken together, paeonol produces protective roles against colitis triggered by DSS, possibly via inhibition of phosphorylation levels of p38 and NF-kappa B p65 not expression of total p38 and NF-kappa B p65. Therefore, paeonol may be a new drug for treating colitis.