The Effect of Dexamethasone on Bleomycin-Induced Lung Fibrosis in the Mouse Model of Systemic Sclerosis

Background and Objectives: Systemic sclerosis (SSc) or scleroderma is a chronic connective tissue disease with unknown etiology. This chronic disease is characterized by vascular changes, immune dysfunction, and internal organ fibrosis. Interstitial lung disease (ILD) is a frequent complication and a major cause of mortality in SSc patients. So far, no effective treatment has been identified for this disease. Based on the evidence proposing inflammation as the primary cause of fibrosis in SSc, administration of glucocorticoids has been suggested for the treatment of SSc-ILD. This study was conducted with the aim of investigation of the therapeutic effect of dexamethasone in the mouse model of systemic sclerosis. Methods: In this experimental study, bleomycin was injected subcutaneously into BALB/c mice to induce pulmonary fibrosis. For intervention with dexamethasone, the mice intraperitoneally received 14 doses of the drug. To determine the effectiveness of dexamethasone, histopathological evaluation of lung fibrosis, was performed by Masson's trichrome staining. Results: In this investigation, bleomycin induced severe pulmonary severe lung fibrosis, and injection of dexamethasone significantly decreased collagen deposition and lung fibrosis (p<0.0001). Conclusion: The results of this study indicated that dexamethasone can reduce bleomycin-induced pulmonary fibrosis in the mouse model of SSc; therefore, treatment with dexamethasone can be useful in inhibiting pulmonary fibrosis in the patients with SSc.