Histochemical quantification of collagen content in articular cartilage

• DOI: 10.1371/journal.pone.0224839
• Publication Date: 2019-11-07T13:49:21Z
• Authors: Lassi Rieppo; Lauriane Janssen; Krista Rahunen; Petri Lehenkari; Mikko A. J. Finnilä; Simo Saarakkala
• Keywords: Trichrome; Masson's trichrome stain; Safranin; Type II collagen; Trichrome stain; Densitometry; Type I collagen

Articular cartilage (AC) is mainly composed of water, type II collagen, proteoglycans (PGs) and chondrocytes. The amount PGs in AC routinely quantified with digital densitometry (DD) from Safranin O-stained sections, but it unclear whether similar method could be used for collagens.The aim this study was to clarify collagens can histological sections using DD.Sixteen human samples were stained Masson's trichrome or Picrosirius red. Optical densities stains compared two commonly collagen parameters (amide I CH2 side chain peak at 1338cm-1) measured Fourier Transform Infrared (FTIR) spectroscopic imaging.Optical density Modified staining, which included enzymatic removal before correlated significantly FTIR-derived almost all depths cartilage. other studied staining protocols displayed significant correlations the reference only few depth layers.Based on our findings, modified protocol suitable quantification content. Enzymatic prior critical as us allows better collagen. Further optimization may improve results future studies.