Melatonin Regulates Oxidative Stress-induced Premature Senescence In Mesenchymal Stem Cells And The Molecular Mechanism Research Of SIRT1-dependent Pathway

[Objective]:Mesenchymal stem cells(MSCs) have a broad application prospect because of their regeneration potential, but they are vulnerable to oxidative stress-induced premature senescence in pathological conditions. Previous studies had proved antioxidant and antiarthritic effects of melatonin on MSCs against proinflammatory cytokines. The purpose of this study was to demonstrate whether melatonin could protect MSCs from premature senescence induced by hydrogen peroxide(H2O2) via the silent information regulator type 1(SIRT1)-dependent pathway.[Methods]:MSCs was induced into premature senescence by treating with a sublethal concentration hydrogen peroxide(H2O2). The effects of melatonin on premature senescence of MSCs were appraised in many ways, cell proliferation was evaluated using the Cell Counting Kit-8, the variation of percentage of SA-β-gal-positive cells using an SA-β-gal staining kit, cell cycle distribution analysis was assessed by PI staining, the osteogenic differentiation potential of MSCs was estimated by Alizarin Red S staining and PCR, Western blot revealed the underlying mechanism involving the signaling pathway.[Results]:In response to H2O2 at a sublethal concentration of 200 μM, human bone marrow-derived MSCs underwent growth arrest and cellular senescence. Treatment with melatonin subsequent to H2O2 exposure successfully improved cell proliferation, decreased senescence-associated β-galactosidase activity, increased proportion in the S phase,enhanced the osteogenic differentiation potential of MSCs that was inhibited by H2O2-induced premature senescence and showed a declining dose-dependent tendency in response to melatonin.We also found that melatonin attenuated the H2O2-stimulated phosphorylation of p38 mitogen-activated protein kinase, decreased expression of the senescence-associated protein p16INK4 a, and increased SIRT1. Further molecular experiments revealed that luzindole or sirtinol blocked melatonin-mediated antisenescence effects.[conclusion]Melatonin reverses H2O2-induced premature senescence in mesenchymal stem cells via the SIRT1-dependent pathway.