Mechanism of Macrophage Action in Osteoarthritis

Osteoarthritis (OA) is the most common chronic joint disease and the main cause of pain and disability in adults (typical clinical OA characteristics), and women are more predisposed to this disease than men. About 400 million people worldwide and more than 100 million in China suffer from arthritis. OA was named the 11th largest contributor of mortality in the world, with a disability rate of as high as 53%, and is among the three major killers threatening the health of the elderly. Colloquially, OA is called the “number one disabling disease of the 21st century.” It is the main reason for the malfunctioned mobility of the elderly. Generally, women and men start to have OA at 40 and 50, respectively. Incidence rates increased dramatically between the ages of 55 and 60. The prevalence rate among older persons over 70 years of age is almost 80–90%. In addition, the disease is a chronic progressive disease, which can not only lead to the decline of life function and the reduction or even loss of quality of life, but also has an important and huge impact on health care and social costs. This disease may also demand higher economic requirements of the affected families. Until now, since the pain mechanism of the disease is not clear, there are no effective treatment methods, and surgical joint replacement is the only choice to treat the end-stage disease. This paper focuses on the role of macrophages in OA development, with particular attention to the occurrence of pain and possible mediators involved.