The Effect of Macrolides on Myofibroblast Differentiation and Collagen Production in Nasal Polyp–Derived Fibroblasts

Abstract

Macrolides are known to have anti-inflammatory, immunomodulatory, and tissue reparative effects. The purpose of this study was to determine the effect of macrolides (erythromycin [EM] and roxithromycin [RXM]) on the differentiation of fibroblasts into myofibroblasts and extracellular matrix accumulation in transforming growth factor (TGF) beta1-induced nasal polyp-derived fibroblasts (NPDFs) and to determine if NADPH oxidase (Nox) 4 and reactive oxygen species (ROS) are involved in the aforementioned processes. Nasal polyps of six patients (three women and three men; 32.3 ± 5.2 years of age) were acquired during surgery and NPDFs were isolated from surgical tissues. NPDFs were pretreated with macrolides for 2 hours before differentiation induction by TGF-beta1. The mRNA expressions of alpha-smooth muscle actin (SMA), collagen types I and III, and Nox4 were determined by reverse-transcription-polymerase chain reaction, and the expression of alpha-SMA protein was determined by immunocytochemical staining. The amount of total collagen production was analyzed by SirCol collagen dye-binding assay. ROS activity was measured by nitroblue tetrazolium reduction assay and was visualized by fluorescent microscopy. In TGF-beta1-induced NPDFs, EM, and RXM significantly inhibited expressions of alpha-SMA and collagen types I and III mRNA and reduced alpha-SMA and collagen protein levels at concentrations of 5 and 10 μg/mL. EM and RXM also inhibited TGF-β1-induced ROS production and Nox4 mRNA expression at the same concentrations. These results suggest the possibility that EM and RXM may play an important role in inhibiting the development of nasal polyps through their antioxidant effect.