Toxicity and oxidative stress responses induced by nano- and micro-CoCrMo particles

Metal implants are used routinely during total hip and knee replacements and are typically composed of cobalt chromium molybdenum (CoCrMo) alloys. CoCrMo “wear particles”, in the nano- and micro-size ranges, are generated in situ. Meanwhile, occupational exposure to CoCrMo particles may be associated with the development of industrial dental worker's pneumoconiosis. In this study, we report that both nano- and micro-CoCrMo induced a time and dose-dependent toxicity in various cell types (i.e. lung epithelial cells, osteoblasts, and macrophages), and the effects of particle size on cell viability and oxidative responses were interesting and cell specific. Our findings highlight the potential roles that nano- and micro-CoCrMo, whether exposure is due to inhalation or implant wear, and the associated oxidative stress may play in the increasingly reported implant loosening, osteolysis, and systemic complications in orthopaedic patients, and may explain the risk of lung diseases in dental workers.