Measurement of matrix metalloproteinase 9-mediated Collagen type III degradation fragment as a marker of skin fibrosis

Skin fibrosis was induced by daily injections of Bleomycin to a total of 52 female C3 H mice, while control mice (n = 28) were treated with phosphate buffered saline (PBS), for 2, 4, 6 or 8 weeks. Skin fibrosis was evaluated using Visiopharm software on Sirius-red stained skin sections. Urine ELISA assays and creatinine corrections were performed to measure CO3-610 levels.CO3-610 levels were significantly higher in Bleomycin-treated vs. PBS-treated mice at each time point of termination. The mean increases were: 59.2%, P < 0.0008, at 2 weeks; 113.5%, P < 0.001, at 4 weeks; 136.8%, P < 0.0001 at 6 weeks; 157.2%, P < 0.0001 at 8 weeks). PBS-treated mice showed a non-significant increase in CO3-610 levels (mean increase for weeks 2-8 = 1.7%, P = 0.789) CO3-610 levels assayed in urine were statistically significantly correlated with Western blot analysis showing increased skin fibrosis (P < 0.0001, r = 0.65).Increased levels in mouse urine of the MMP-9 mediated collagen III degradation fragment CO3-610 were correlated with skin fibrosis progression, suggesting that CO3-610 may be a potential positive biomarker to study the pathogenesis of skin fibrosis in mice.The extracellular matrix (ECM) is the major component of connective tissue. It consists mainly of proteoglycans, glycoprotein and collagens, all of which have important and unique roles in maintaining the physicochemical structure of tissue [1-3]. Fibrotic skin diseases share a number of common phenotypic manifestations, particularly the accumulation of collagen, indicating a disturbed balance in ECM remodelling (ECMR) [4]. Matrix metalloproteinases (MMPs) play a central role in the proteolytic degradation of collagens and other extracellular molecules, resulting in the generation of specific cleavage fragments of proteins which in turn produce new epitopes. These neo-epitopes may be used as disease markers in a specific organ or in a specific disease.In fibrosis, which may be described as extensive scar formation