Indeed, analyzing CCl4-induced liver fibrosis in PAR-2-deficient compared to wild-type mice, Knight et al. found a reduced progression of liver fibrosis, hepatic collagen gene expression, hydroxyproline content, TGF-β expression, and matrix metalloproteinase 2 gene expression in the absence of PAR-2. This evidence concerns the gene MMP2 and Hepatic fibrosis.