Faculty Bibliography

Chronic low-back pain (CLBP) is one of the most common pain conditions. Current clinical guidelines for low-back pain recommend acupuncture for CLBP. However, there are very few high-quality acupuncture studies on CLBP in older adults. Clinical acupuncture experts in the American Traditional Chinese Medicine Association (ATCMA) were interested in the recent grant on CLBP research announced by the National Center for Complementary and Integrative Health. The ATCMA experts held an online discussion on the subject of real-world acupuncture treatments for CLBP in older adults. Seven participants, each with more than 20 years of acupuncture practice, discussed their own unique clinical experience while another participant talked about the potential mechanism of acupuncture in pain management. As a result of the discussion, a picture of a similar treatment strategy emerged across the participants for CLBP in older adults. This discussion shows that acupuncture may have complicated mechanisms in pain management, yet it is effective for the treatment of chronic pain involving maladaptive neuroplasticity; therefore, it should be effective for CLBP in older adults.

Microglia, which comprise a sensor for pathological events in the central nervous system, may be triggered by nerve injury and transformed from a quiescent state into an activated state; ionised calcium binding adaptor molecule 1 (Iba1) is a sensitive marker associated with activated microglia. Accumulated evidence suggests that spinal activated microglia and the brain-derived neurotrophic factor (BDNF)-tyrosine kinase receptor B (TrkB) signalling pathway play major roles in the production and development of neuropathic pain. Electro-acupuncture (EA) has a positive effect on relieving chronic neuropathic pain; however, the underlying mechanisms remain unclear. To determine the significance of EA in the treatment of neuropathic pain mediated by activated microglia and the BDNF-TrkB signalling pathway in the spinal cord, the mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) values were recorded to assess hyperalgesia and allodynia. In addition, the amount of activated microglia and BDNF were assessed via immunofluorescence. Iba1, BDNF and TrkB mRNA expression levels were examined using qPCR; the protein levels of BDNF, p-TrkB and TrkB in the spinal cord were analysed via western blotting. The present study demonstrated that EA treatment increased the MWT and TWL values. EA significantly inhibited the proportion of activated microglia and BDNF expression in the spinal cord after chronic constrictive injury (CCI). Furthermore, EA decreased the expression of BDNF and TrkB at both the mRNA and protein levels in the spinal cord of CCI rats. These findings suggest that the analgesic effect of EA may be achieved by inhibiting the activation of spinal microglia and subsequently blocking the BDNF-TrkB signalling pathway.

Potassium-chloride cotransporter 2 (KCC2) has been indicated to serve a crucial role during chronic neuropathic pain (NP). Following the emergence of NP, γ‑aminobutyric acid (GABA) A receptor‑mediated signaling may be further impaired by the changes of KCC2 chloride anion gradient. In the present study, the authors investigate the effect of electro-acupuncture (EA) on the behavior and the expression of KCC2 and GABAA receptor γ2 subunit in the spinal cord of chronic constriction injury (CCI) model rats. A total of 60 adult male Sprague‑Dawley rats were divided into four groups: Normal group, sham‑CCI group, CCI group and CCI+EA group. The effect of EA was assessed via the values of mechanical withdrawal threshold and thermal withdrawal latency, which were significantly improved upon stimulation of the ST‑36 and GB‑34 acupoints. In addition, a marked reduction in both the mRNA and protein levels of KCC2 and GABAA receptor γ2 subunit was observed in the spinal cord following loose ligation of the sciatic nerve. The reductions in KCC2 and GABAA receptor γ2 subunit expression were reversed by EA treatment. These results support the notion that KCC2 and GABAA receptor γ2 subunit contribute to NP following peripheral nerve injury and extend the understanding of the analgesic effects of EA on NP.