Modulation of inflammatory mediators by corydalis tuber in LPS-stimulated Raw264.7 cells and its inhibitory effects on carrageenan-stimulated paw edema in rats

Abstract

The present study was conducted to evaluate the effect of methanol extract of Corydalis Tuber (CTE) on the levels of inflammatory mediators in Raw264.7 cells activated by lipopolysaccharide (LPS), and on paw edema in rats. CTE dose-dependently decreased release of nitric oxide (NO) and prostaglandin E2 (PGE2), which elevated by LPS. The inhibitions of NO and PGE2 by CTE were due to the suppression of iNOS expression and of COX-2 activity, respectively. CTE also inhibited the nuclear translocation of nuclear factor kappa B (NF-κB) and the phosphorylation of inhibitory kappa B (IκB), determined by western blot analysis. In addition, CTE inhibited the production of TNF-α, interleukin-1β (IL-1β) and interleukin-6 (IL-6). Furthermore, administration of CTE significantly inhibited the formation of paw edema by carrageenan in rats. Histopathologically, CTE effectively inhibited increases of hind paw skin thickness and inflammatory cell infiltrations. These findings demonstrate that CTE has inhibitory effect on inflammatory markers in LPS-activated Raw264.7 cells and on paw edema in carrageenan-stimulated rats, showing the possibility of anti-inflammatory use of Corydalis Tuber.