Qingxi Cao, Yuehua Li

Department of Sports Medicine, The People’s Hospital of Baoan Shenzhen, Shenzhen, Guangdong Province, People’s Republic of China

Correspondence: Yuehua Li, Department of Sports Medicine, The People’s Hospital of Baoan Shenzhen, Shenzhen, Guangdong Province, 518100, People’s Republic of China, Tel +13560331881, Email 18525428109@163.com

Abstract: Knee osteoarthritis (KOA) is a prevalent degenerative joint disorder characterized by synovitis, cartilage degradation, and nociception, in which dysregulated immune responses and excessive proinflammatory mediators drive synovial inflammation as a central pathogenic mechanism. Acupuncture, a cornerstone of traditional Chinese medicine, has demonstrated clinical efficacy in alleviating pain, attenuating synovial pathology, and restoring joint function in KOA. In this review, we systematically elucidate the molecular mechanisms by which acupuncture suppresses synovial inflammation, focusing on its multimodal modulation of five critical signaling cascades: norepinephrine (NE) signaling, the TLRs/NFκB pathway, the MCP1/CCR2 axis, the NLRP3 inflammasome, and the RasRafMEK1/2ERK1/2 pathway. Relevant studies published between 2000 and 2024 were identified through comprehensive searches of PubMed and CNKI using terms such as “acupuncture + synovitis + MAPK pathway”, “acupuncture + inflammation”, and “knee osteoarthritis + molecular mechanisms”. English and Chinese peerreviewed articles reporting preclinical or clinical data on acupuncture’s effects in KOA synovitis were included, while studies lacking mechanistic insights or unrelated to synovial inflammation were excluded. Study validity, risk of bias, and methodological rigor were appraised using the GRADE framework. Cumulative evidence indicates that acupuncture exerts antiinflammatory and chondroprotective effects by orchestrating multipathway regulation, thereby reducing inflammatory mediators, promoting tissue repair, and improving joint function. As a promising adjunct to pharmacotherapy—particularly in earlystage KOA—acupuncture merits further validation through largescale clinical trials aimed at optimizing treatment parameters, confirming longterm efficacy, and exploring synergistic combinations with emerging therapies to enable personalized KOA management.

Keywords: knee osteoarthritis, synovial inflammation, acupuncture, signaling pathway