Recent development in understanding the role of lipids in cartilage lubrication

Lubrication deficiency of articular cartilage (AC) triggers irreversible and progressive degradation of AC, termed osteoarthritis (OA). Bio-lubrication-based strategies have been proposed as an effective way to restore temporary cartilage lubrication for OA postponement or even OA healing. The design of lubricants has inspired an exploration of the reasons behind the low friction in cartilage and the components responsible for the lubrication function in cartilage. Recently, lipids as an emerging lubrication component in AC, have been extensively studied and confirmed to play an essential role in maintaining cartilage lubrication. This review brought forward the main challenges of establishing a satisfactory functional articular cartilage biomaterial with sufficient lubrication from the perspectives of the complexity of physiology and microenvironment of osteochondral tissue. Then, we comprehensively discussed lubrication models of AC, including the lubrication mechanism of AC, OA association with lipids, lipid lubrication mechanism and application, and the synergistic effects of phospholipids in lubrication. Especially, we highlighted the advantages and application of lipids and their derivatives in lubrication. Finally, we analyzed the future perspectives of lipid-based biomaterials to achieve the perfect treatment of OA. This comprehensive and instructive review could provide deep insights into our current understanding of lipids and lubrication-related diseases.