Animal models in systemic sclerosis.

Systemic sclerosis (SSc) is a complex systemic disease. It is characterised by fibrosis, of the skin and internal organs, as lungs, kidney, heart and gastrointestinal tract. As the aetiology of SSc is unknown, numerous animal models have been developed to better understand the pathogenesis of the disease and to test potentially useful therapeutic interventions. Although several animal models have been described, predominantly in mice, none reproduces precisely all manifestations of SSc. However, all animal models display tissue fibrotic changes similar to those present in SSc. This review is focused on the principal animal models and the molecular pathways involved. Animal models can be divided into two groups. In one group the pathologic phenotype is the result of a genetic mutation ( tight skin 1 and tight skin 2,UCD 200). In the second group, the pathologic alterations are induced in normal animals by manipulation of their immune system (sclerodermatous graft-vs-host disease (Scl GVHD) induced by transplantation, or by administration of exogenous substances). In the future, the development of additional animal models may become important in the further understanding of the alteration of the molecular pathways that regulate a physiologic processes to induce tissue fibrosis, the hallmark of this disease, and to identify and test targeted therapeutic agents.