“…From in vitro studies, matrix metalloproteinases (MMPs), including MMP-1, -9, -13, and -14, can effectively degrade native Col-I fibers surrounding a cell surface through the glycine in Col-I fibers (Aimes and Quigley, 1995;Bigg et al, 2007;Fini et al, 1992;Knauper et al, 1997). In addition, the degradation of Col-I, -II, and -III fibers using various temperature-dependent treatments has been investigated (Cárcamo et al, 2012;Jain et al, 2014; Contents lists available at ScienceDirect Su et al, 2014). Methods for analyzing the degradation of Col-I fibers include the enzyme-linked immunosorbent assay and highperformance liquid chromatography (Akhtar et al, 1999;Hudson et al, 2012), which have excellent sensitivity for the detection of specific degraded enzymes in Col-I fibers.…”