Silica promotes the transdifferentiation of rat circulating fibrocytes in vitro

To investigate the effects of silica on circulating fibrocytes (cFbs), the present study established a primary culture model of rat alveolar macrophages and cFbs in vitro. Macrophages were treated with free silica, and their supernatant was used to stimulate cFbs. The mRNA expression levels of collagen I, collagen III and α-smooth muscle actin (SMA) in cFbs were analyzed by reverse transcription-quantitative polymerase chain reaction. The intracellular and extracellular protein expression levels of collagen I, collagen III and α-SMA were detected by ELISA and immunofluorescence staining. The results indicated that in the cell model, the free silica effectively increased the protein and mRNA expression levels of collagen-I, collagen-III and α-SMA. The free silica significantly promoted the transdifferentiation of cFbs into myofibroblasts in a dose-and time-dependent manner.