Loss of collagen content is localized near cartilage lesions on the day of injurious loading and intensified on day 12

Joint injury can lead to articular cartilage damage, excessive inflammation, and post-traumatic osteoarthritis (PTOA). Collagen is an essential component for cartilage function, yet current literature has limited understanding of how biochemical and biomechanical factors contribute to collagen loss in injured cartilage. Our aim was to investigate spatially dependent changes in collagen content and collagen integrity of injured cartilage, with an explant model of early-stage PTOA. We subjected calf knee cartilage explants to combinations of injurious loading (INJ), interleukin-1α-challenge (IL) and physiological cyclic loading (CL). Using Fourier transform infrared microspectroscopy, collagen content (Amide I band) and collagen integrity (Amide II/1338 cm