An in vivo stable isotope labeling method to investigate individual matrix protein synthesis, ribosomal biogenesis, and chondrocyte proliferation in murine articular cartilage

These experiments have used a stable-isotope method using <em>in vivo</em> deuterium oxide labeling and mass spectrometry to measure protein concentration, protein half-life, cell proliferation, and ribosomal biogenesis in a single sample of murine articular cartilage. We hypothesized that a 60-day labeling period would capture age-related declines in cartilage matrix protein content, protein synthesis rates, and chondrocyte proliferation. Knee cartilage was isolated from 25- and 90-week-old female C57BL/6J mice treated with deuterium oxide for 15, 30, 45 and 60 days. We measured protein abundance and half-lives using high resolution accurate mass spectrometry (HRAM) and d2ome data processing software.