Tissue-Specific and Spatially Dependent Metabolic Signatures Perturbed by Injury in Male and Female Mice

Osteoarthritis, the leading cause of disability worldwide, disproportionately affects women, yet sex remains an overlooked determinant. This disparity stems from sex-specific differences in injury susceptibility-a major risk factor for disease. Using a non-invasive injury model, we demonstrate that injury drives local and systemic metabolic alterations and that these responses differ by sex.

Male and female mice were subjected to non-invasive joint injury. Eight days after injury, serum, synovial fluid, and whole joints were collected for metabolomics. Additionally, whole joints were harvested for matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) to capture the spatial distribution of molecular species and identify osteochondral regions perturbed by injury.

Comparative analyses among injured, contralateral, and naive mice revealed metabolomic alterations across sample types. Data indicate that injury influences metabolic profiles in whole joints, synovial fluid, and serum, with consistent dysregulation of amino acid, purine, and pyrimidine metabolism, indicating a systemic effect of localized injury. Additionally, sex-dependent differences emerged across tissues, highlighting sexually dimorphic pathways following injury. MALDI-MSI generated 2D ion images of bone, the joint interface, and bone marrow, identifying region-specific metabolic changes following injury.

Joint injury induces coordinated metabolic responses locally and systemically that extend beyond the injured joint and are influenced by sex. Integrating metabolomic and spatial analyses reveals how injury modulates joint pathophysiology across tissues and reveals sex-specific patterns relevant to post-traumatic osteoarthritis (PTOA) risk. These findings improve preclinical PTOA models and deepen our understanding of the complex role of injury and sex in osteoarthritis pathogenesis, laying the foundation for targeted therapeutic strategies.