Experimental Mouse Model of Bleomycin‐Induced Skin Fibrosis

Abstract Systemic sclerosis (SSc) refers to an autoimmune disease, which is manifested by inflammation, vasculopathy, and fibrosis of the skin and internal organs. There are a number of different animal models recapitulating specific aspects of SSc. The experimental mouse model of bleomycin‐induced skin fibrosis is commonly used to study the pathogenesis observed in SSc. In this model, repetitive intradermal injections of the cytotoxic agent bleomycin trigger progressive skin thickening, associated with excessive accumulation of collagen, infiltration of immune cells, and formation of α‐smooth muscle actin (α‐SMA)‐positive myofibroblasts. In this article, we provide a detailed protocol for the induction of skin fibrosis in experimental mice by bleomycin. Moreover, we describe procedures for processing and analyzing affected skin tissue, provide troubleshooting, highlight advantages and limitations of the presented model, and critically discuss representative results. © 2019 by John Wiley & Sons, Inc. Basic Protocol 1 : Intradermal bleomycin injections to induce skin fibrosis in mice Support Protocol : Mouse tissue collection for fibrosis evaluation and for other molecular assays Basic Protocol 2 : Evaluation of mouse skin thickness using Masson's trichrome staining Basic Protocol 3 : Measurement of hydroxyproline content in skin tissue using a colorimetric assay Basic Protocol 4 : Evaluation of myofibroblasts in mouse skin by immunohistochemistry