Stage-Specific Mechanisms of Manual Acupuncture and Electroacupuncture in Inflammatory Pain: A Time-Dependent Review

This narrative review synthesizes preclinical evidence from 54 studies to outline the distinct, stage-dependent mechanisms of manual acupuncture (MA) and electroacupuncture (EA) in inflammatory pain. Following a systematic search, we conducted a detailed thematic analysis of studies using CFA-induced rodent models and organized the findings into three pathological phases: acute (1-3 days), subacute (4-14 days), and chronic (>14 days). The results demonstrate a temporal evolution of therapeutic mechanisms that underscores the necessity of stage-specific intervention strategies for optimizing clinical outcomes. In the acute phase, interventions primarily produce rapid analgesia by engaging immediate descending inhibitory pathways and modulating peripheral ion channels. During the subacute phase, treatments work to counteract central sensitization through immune microenvironment reprogramming and the regulation of synaptic plasticity. For the chronic phase, strategies expand beyond pain relief to alleviate neuropsychiatric comorbidities and promote systemic tissue repair via limbic circuit remodeling. By integrating these findings, this work proposes a time-sensitive mechanistic framework. It underscores the principle of "time-window" optimization for precision acupuncture intervention in inflammatory pain, while also pointing to the critical need for future clinical translation and validation.