Multidimensional Pain Modulation by Acupuncture Analgesia: The Reward Effect of Acupuncture on Pain Relief

Neural circuit mechanisms of acupuncture effect: where are we now?

Recently, there has been increasing attention on the impact of acupuncture on the dysregulated neural circuits in different disease. This has led to new understandings of how acupuncture works. This review presents a comprehensive analysis of research that have examined the impact of acupuncture on abnormal neural circuits associated with pain, anxiety, Parkinson's disease, addiction disorders, cognitive problems, and gastrointestinal disorders. These studies have shown that acupuncture's therapeutic effects are mediated by specific brain areas and neurons involved in neural circuit mechanisms, emphasising its wide-ranging influence. The positive impacts of acupuncture can be ascribed to its ability to modify the functioning of neurocircuits in various physiological conditions. Nevertheless, contemporary studies on acupuncture neural circuits frequently overlook the comprehensive circuit mechanism including the periphery, central nervous system, and target organ. Additionally, the scope of diseases studied is restricted. Future study should focus on broadening the range of diseases studied and exploring the neural circuit mechanisms of these diseases in depth in order to enhance our understanding of acupuncture's neurobiological impacts.

Efficacy of acupuncture for whiplash injury: a systematic review and meta-analysis

OBJECTIVES

This study aimed to establish clinical evidence for acupuncture by analysing data from trials that demonstrated the efficacy of acupuncture for whiplash-associated disorder (WAD) with the following research question: Is acupuncture treatment effective for symptom alleviation in patients with WAD compared with other usual care?

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

PubMed, Ovid Medline, Embase, The Cochrane Library, China National Knowledge Infrastructure, ScienceOn, KMBASE, Korean Studies Information Service System, Korea Med, Oriental Medicine Advanced Searching Integrated System and Research Information Sharing Service were searched from their inception to 1 October 2023.

ELIGIBILITY CRITERIA

We included randomised controlled trials (RCTs) using acupuncture on patients with WAD. The outcomes were the pain visual analogue scale (VAS) score or numerical rating scale score for neck pain, the range of motion (ROM) of the neck, the Neck Disability Index and safety.

DATA EXTRACTION AND SYNTHESIS

Two independent researchers analysed and extracted data from the selected literatures. The risk of bias and the quality of evidence were assessed according to the Cochrane Handbook for Systematic Reviews of Interventions and the Grading of Recommendations Assessment, Development, and Evaluation method, respectively.

RESULTS

A total of 525 patients with WAD from eight RCTs were included in this study. The meta-analysis revealed that the outcomes showed significant differences in the pain VAS score (standard mean difference (SMD): -0.57 (-0.86 to -0.28), p<0.001) and ROM-extension (SMD: 0.47 (0.05 to 0.89), p=0.03). The risk of bias assessment revealed that four studies published after 2012 (50%, 4 out of 8 studies) showed low bias in most domains. The pain VAS score was graded as having moderate certainty.

CONCLUSION

Acupuncture may have clinical value in pain reduction and increasing the ROM for patients with WAD. High-quality RCTs must be conducted to confirm the efficacy of acupuncture in patients with WAD.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42021261595.

Electroacupuncture Alleviates Dry Eye Ocular Pain Through TNF-ɑ Mediated ERK1/2/P2X3R Signaling Pathway in SD Rats

Purpose

This study aimed to examine electroacupuncture's influence on ocular pain and its potential modulation of the TNF-ɑ mediated ERK1/2/P2X3R signaling pathway in dry eye-induced rat models.

Methods

Male Sprague-Dawley rats with induced dry eye, achieved through extraorbital lacrimal gland removal, were treated with electroacupuncture. Comprehensive metrics such as the corneal mechanical perception threshold, palpebral fissure height, eyeblink frequency, eye wiping duration, behavioral changes in the open field test, and the forced swimming test were employed. Additionally, morphological changes in microglia and neurons were observed. Expression patterns of key markers, TNF-ɑ, TNFR1, p-ERK1/2, and P2X3R, in the trigeminal ganglion (TG) and spinal trigeminal nucleus caudalis (SpVc) regions, were studied with etanercept serving as a control to decipher the biochemistry of electroacupuncture's therapeutic effects.

Results

Electroacupuncture treatment demonstrated a notable decrease in the corneal mechanical perception threshold, improvement in palpebral fissure height, and significant reductions in both eyeblink frequency and eye wiping duration. Moreover, it exhibited a promising role in anxiety alleviation. Notably, the technique effectively diminished ocular pain by curbing microglial and neuronal activation in the TG and SpVc regions. Furthermore, it potently downregulated TNF-ɑ, TNFR1, p-ERK1/2, and P2X3R expression within these regions.

Conclusion

Electroacupuncture attenuated damage to sensory nerve pathways, reduced pain, and eased anxiety in dry eye-afflicted rats. The findings suggest a crucial role of TNF-ɑ mediated ERK1/2/P2X3R signaling pathway inhibition by electroacupuncture in these benefits.