Joint diseases like osteoarthritis usually are accompanied with inflammatory processes, in which pro-inflammatory cytokines mediate the generation of intracellular reactive oxygen species (ROS) and compromise survival of subchondral osteoblasts. Melatonin is capable of manipulating bone formation and osteogenic differentiation of mesenchymal stem cells (MSCs). The aim of this work was to investigate the anti-inflammatory effect of melatonin on MSC proliferation and osteogenic differentiation in the absence or presence of interleukin-1 beta (IL-1β), which was used to induce inflammation. Our data showed that melatonin improved cell viability and reduced ROS generation in MSCs in a dose-dependent manner. When exposed to 10 ng/mL IL-1β, various concentrations of melatonin resulted in significant reduction of ROS by 34.9% averagely. Luzindole as a melatonin receptor antagonist reversed the anti-oxidant effect of melatonin in MSCs with co-exposure to IL-1β. Real-time RT-PCR data suggested that melatonin treatment up-regulated the expression of CuZnSOD and MnSOD, while down-regulated the expression of Bax. To investigate the effect of melatonin on osteogenesis, MSCs were cultured in osteogenic differentiation medium supplemented with IL-1β, melatonin, or luzindole. After exposed to IL-1β for 21 days, 1 μm melatonin treatment significantly increased the levels of type I collagen, ALP, and osteocalcin, and 100 μm melatonin treatment yielded the highest level of osteopontin. Our study demonstrated that melatonin maintained MSC survival and promoted osteogenic differentiation in inflammatory environment induced by IL-1β, suggesting melatonin treatment could be a promising method for bone regenerative engineering in future studies.
Low‐cost preparation methods for cathodes with high capacity and long cycle life are crucial for commercializing potassium‐ion batteries (PIBs). Presently, the charging/discharging strain that develops in the active cathode material of PIBs causes cracks in the particles, leading to a sharp capacity fade. Here, to abate the strain release and the need for an industrially relevant process, a simple low‐cost co‐precipitation method for synthesizing yolk–shell P3‐type K0.5[Mn0.85Ni0.1Co0.05]O2 (YS‐KMNC) was reported. As cathode material for PIBs, the YS‐KMNC delivers a high reversible capacity (96 mAh g–1 at 20 mA g–1) and excellent cycle stability (80.5% retention over 400 cycles at a high current density of 200 mA g–1). More importantly, a full battery assembled with the YS‐KMNC cathode and a commercial graphite anode exhibits a high operating voltage (0.5‐3.4 V) and an excellent cycling performance (84.2% retention for 100 cycles at 100 mA g–1). Considering the low‐cost, simple production process and high performance of YS‐KMNC cathode, this work could pave the way for the commercial development of PIBs.
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