Effect of [6]-gingerol on myofibroblast differentiation in transforming growth factor beta 1-induced nasal polyp-derived fibroblasts

Background: [6]-Gingerol is one of the major pungent principles of ginger and has diverse effects, including anti-inflammatory, and antioxidative effects. Reactive oxygen species (ROS) are released during the phenotypic transformation of fibroblasts to myofibroblasts, a process that is involved in the growth of nasal polyps by inducing extracellular matrix (ECM) accumulation. The purpose of this study was to determine the effect of [6]-gingerol on myofibroblast differentiation and collagen production of nasal polyp- derived fibroblasts (NPDFs) and to determine if the effect of [6]-gingerol is linked to an antioxidant effect. Methods: NPDFs were incubated and treated with transforming growth factor (TGF) beta 1. The ROS generated by NPDFs were determined using 2″,7″-dichlorfluorescein-diacetate. The fluorescence was captured by a fluorescent microscope and measured using a fluorometer. The expression of alpha-smooth muscle actin (SMA) and collagen type IV mRNA was determined by a reverse transcription-polymerase chain reaction, and the expression of α-SMA protein and pSmad2/3 was determined by immunofluorescence microscopy and or Western blotting. The amount of total soluble collagen production was analyzed by the SirCol collagen dye-binding assay. Results: TGF-beta 1 stimulation increased ROS production by NPDFs. [6]-Gingerol decreased the production of ROS in TGF-beta 1-induced NPDFs. Myofibroblast differentiation, collagen production, and phosphorylation of Smad2/3 were prevented by [6]-gingerol and inhibition of ROS generation with antioxidant such as diphenyliodonium, N-acetylcysteine, and ebselen. Conclusion: These results suggest the possibility that [6]-gingerol may play an important role in inhibiting the production of the ECM in the development of nasal polyps through an antioxidant effect.