Assessment of renal fibrosis and anti‐fibrotic agents using a novel diagnostic and stain‐free second‐harmonic generation platform

Current histological measurement techniques for interstitial collagen, the basis of interstitial fibrosis, are semi‐quantitative at best and only provide a ratio of collagen levels within tissues. The Genesis200 imaging system and supplemental image analysis software, FibroIndex from HistoIndex, is a novel, automated platform that uses second‐harmonic generation (SHG) for imaging and characterization of interstitial collagen deposition and additional characteristics, in the absence of any staining. However, its ability to quantify renal fibrosis requires investigation. This study compared SHG imaging of renal fibrosis in mice with unilateral ureteric obstruction (UUO), to that of Masson’s trichrome staining (MTS) and immunohistochemistry (IHC) of collagen I. Additionally, the platform generated data on collagen morphology and distribution patterns. While all three methods determined that UUO‐injured mice underwent significantly increased renal fibrosis after 7 days, the HistoIndex platform additionally determined that UUO‐injured mice had a significantly increased collagen‐to‐tissue cross reticulation ratio (all P