The efficacy of acupuncture in treating pain diseases has been recognized in clinical practice, and its mechanism of action has been a hot topic in academic acupuncture research. Previous basic research on acupuncture analgesia has focused mostly on the nervous system, with few studies addressing the immune system as a potential pathway of acupuncture analgesia. In this study, we investigated the effect of electroacupuncture (EA) on the β-endorphins (β-END) content, END-containing leukocyte type and number, sympathetic neurotransmitter norepinephrine (NE), and chemokine gene expression in inflamed tissues. To induce inflammatory pain, about 200 µL of complete Frester adjuvant (CFA) was injected into the unilateral medial femoral muscle of adult Wistar rats. Electroacupuncture treatment was performed for 3 days beginning on day 4 after CFA injection, with parameters of 2/100 Hz, 2 mA, and 30 minutes per treatment. The weight-bearing experiment and enzyme-linked immunosorbent assay showed that EA treatment significantly relieved spontaneous pain-like behaviors and increased the level of β-END in inflamed tissue. Injection of anti-END antibody in inflamed tissue blocked this analgesic effect. Flow cytometry and immunofluorescence staining revealed that the EA-induced increase in β-END was derived from opioid-containing ICAM-1⁺/CD11b⁺ immune cells in inflamed tissue. In addition, EA treatment increased the NE content and expression of β2 adrenergic receptor (ADR-β2) in inflammatory tissues and upregulated Cxcl1 and Cxcl6 gene expression levels. These findings provide new evidence for the peripheral analgesic effect of acupuncture treatment by recruiting β-END–containing ICAM-1⁺/CD11b⁺ immune cells and increasing the β-END content at the site of inflammation.

Background: The objective of this pilot study was to evaluate the cerebral effects of laser stimulation and traditional needle acupuncture in patients after stroke. Methods: Seventeen stroke patients (12 female and five male; mean age ± SD: 66.5 ± 12.9 years) were randomly selected in a stroke rehabilitation hospital. Patients’ regional cerebral blood oxygen saturation (rSO2) values were recorded before, during, and after needle acupuncture (scalp, ear and body) as well as before, during, and after corresponding laser stimulation (red laser, four points: 100 mW, 658 nm, 500 µm; yellow laser, one point: 50 mW, 589 nm, 500 µm; infrared laser, three points: 100 mW, 810 nm, 500 µm; green laser, one point: 5 mW, 532 nm, 500 µm) in a cross-over study design. Results: There were no significant changes after needle acupuncture in the phases immediately after needle insertion or during acupuncture stimulation. However, after manual needle acupuncture and after laser stimulation, the majority of the rSO2 values showed increases. The highest value (+3%) was reached after laser stimulation treatment. Heart rate and blood pressure before and after the treatments did not show significant alterations. Conclusions: Changes in local cerebral oxygen saturation could be quantified, although confirmation may only be expected after extensive follow-up studies.