Objective: The antifibrotic effect of simvastatin has been demonstrated in human lung fibroblasts. This study aimed to measure the effects of simvastatin in the development of pulmonary and cutaneous fibrosis in a murine model of SSc and to explore the mechanisms of these effects.
Methods: Chronic oxidant stress SSc was induced in BALB/c mice by daily s.c. injections of HOCl for 6 weeks. Mice were randomized in three arms: treatment with HOCl, HOCl plus simvastatin or vehicle alone. Statin treatment was initiated 30 min after HOCl s.c. injection and continued daily for 6 weeks. Skin and lung fibrosis were evaluated by histological methods. Immunohistochemical staining for α-smooth muscle actin in cutaneous and pulmonary tissues was performed to evaluate myofibroblast differentiation. Lung and skin concentrations of VEGF, extracellular signal-related kinase (ERK), rat sarcoma protein (Ras), Ras homologue gene family (Rho) and TGF-β were analysed by western blot.
Results: Injections of HOCl induced cutaneous and lung fibrosis in BALB/c mice. Simvastatin treatment prevented both skin thickness and pulmonary fibrosis. Myofibroblast differentiation was also inhibited by simvastatin in the skin and in the lung. Increased cutaneous and pulmonary expression of VEGF, ERK, Ras and Rho in mice treated with HOCl was significantly lower in mice treated with HOCl plus simvastatin.
Conclusion: Simvastatin reduces the development of pulmonary fibrosis, potentially modulating adverse lung remodelling, as shown by the reduced deposition of collagen in alveolar septae. Simvastatin also reduces skin thickness in this model.
Keywords: animal model; pulmonary fibrosis; reactive oxygen species; simvastatin; systemic sclerosis.