Effects of auricular point acupressure on inflammatory signaling in chronic low back pain: a secondary analysis of a randomized controlled trial.

OBJECTIVE: Auricular point acupressure (APA) has shown promise for pain relief, but its biological mechanisms remain unclear. This study examined the effects of APA on inflammatory cytokines and explored the relationships between changes in inflammatory markers and clinical outcomes in older adults with chronic low back pain (cLBP). METHOD: This secondary analysis utilized plasma samples from a three-arm randomized controlled trial (RCT) (NCT03589703) with 272 participants aged 65 years and older with cLBP. The participants were randomly assigned (1:1:1) to the targeted APA (T-APA), nontargeted APA (NT-APA), or education control (CG) groups for four weeks. Cytokine levels were measured at baseline, post-intervention, and at the one- and three-month follow-ups using multiplex assays. RNA sequencing and quantitative PCR (qPCR) were performed to assess changes in inflammatory gene expression. The primary outcome was the change in inflammatory cytokine levels, and the secondary outcomes included self-reported pain and physical function. RESULTS: A total of 272 participants were randomized (T-APA: 92, NT-APA: 91, CG: 89), with 43.4% completing follow-up. The participants in the T-APA group showed significant reductions in the levels of proinflammatory cytokines (IL-2, IL-8, and TNF-α) and increases in the levels of the anti-inflammatory cytokine TGF-β. These changes correlated with improvements in pain and physical function.Gene expression analysis suggested the modulation of CXCL8 and GPS2, indicating the potential influence of APA on neuroimmune signaling. The NT-APA and CG groups did not show similar benefits. No serious adverse events were reported. CONCLUSION: These findings suggest that APA has immune-modulating effects on reducing inflammation and improving pain outcomes in older adults with cLBP. However, the discrepancies between the RNA sequencing and qPCR results warrant further investigation into the molecular mechanisms of APA. Future studies should incorporate longer follow-up periods and larger sample sizes to validate these findings. TRIAL REGISTRATION: Trial ID: NCT03589703 (registration date: May 22, 2018).