Mechanism of electrothermal acupuncture in alleviating postherpetic neuralgia

To investigate the mechanism of electrothermal acupuncture in alleviating postherpetic neuralgia (PHN).

A rat model of PHN was created with RTX injection, and electrothermal acupuncture (ETA) was applied at trigger points. Pain sensitivity was assessed using the von Frey test for PWT. ATP levels were measured colorimetrically, ROS via DCFH-DA fluorescence, and pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) in tissues using ELISA. DEGs were identified through RNA sequencing, followed by GO and KEGG analyses, and PPI networks were constructed to identify core genes. Real-time quantitative PCR (RT-qPCR) for detecting gene expression levels.

ETA significantly increased PWT values, confirming its analgesic effect. Moreover, compared to the PHN group, ETA treatment significantly attenuated RXT-induced increases in the levels of IL-1β, IL-6, and TNF-α (p < 0.05). It also reversed the RXT-induced excessive ATP elevation and abnormal ROS accumulation in both tissues (p < 0.01), with ETA intervention showing particularly marked suppression of ROS in spinal cord tissue. Differential expression analysis identified 822 DEGs in muscle tissue and 333 in spinal cord tissue. The intersection of these datasets yielded 48 candidate genes that were significantly enriched in interferon-mediated innate immune-related pathways. Using the cytoHubba plugin, five core genes-Mx1, Irf7, Rtp4, Oasl2, and Ifit1bl-were identified through multiple algorithmic screenings. RT-qPCR validation confirmed that ETA intervention significantly upregulated the expression levels of Mx1, Irf7, Rtp4, Oasl2, and Ifit1bl (p < 0.05).

ETA alleviates tactile allodynia induced by RTX in rats, at least in part by upregulating the expression of type I interferon-related genes (Mx1, Irf7, Rtp4, Oasl2, and Ifit1bl). This upregulation suppresses the central and peripheral inflammatory responses associated with PHN, while also modulating energy metabolism and redox homeostasis in pain-related tissues. These findings offer novel mechanistic insights supporting the use of ETA as an adjunctive therapy for neuropathic pain management.