Project description:This study was aimed at understanding the effects of menopause on knee osteoarthritis, specifically the cartilage proteome. Middle-aged female mice were randomized to receive intraperitoneal injections of either 4-vinylcyclohexene diepoxide (VCD) or sesame oil for 10 consecutive days. Through a serious of validation experiments, we and others have shown that VCD induces a menopausal phenotype, as evidenced by loss of estrus cyclicity and modification to sex hormone profiles. We also showed in our work that VCD injected mice present with more severe cartilage degeneration than sesame oil injected mice. Knee cartilage from the tibial plateau and femoral condyles were microdissected at mid-perimenopause (75 days after the first injection), start of menopause (115 days after the first injection), and late menopause (195 days after the first injection). These times points were chosen since cartilage pathology first presented in the VCD group, but not the sesame oil group, at the start of menopause. Cartilage samples were lyophilized and mass spectrometry proteomics were performed.