Purpose Macrophage polarization contributes to the mechanisms of treating knee osteoarthritis (KOA). In previous studies, fire needling acupuncture has been shown to affect KOA favorably. However, the mechanism of fire needling acupuncture on macrophage polarization is not well-defined. Thus, this study was conducted to determine that fire needling acupuncture exerts a therapeutic role in KOA by modulating macrophage polarization. Methods Thirty mice were allocated at random into three groups of ten. The groups were labeled as “control”, “model”, and “fire needling acupuncture”. Each group consisted of ten mice. From the second day of intra-articular injection MIA, the right “xiyan” (EX-LE5), “dubi” (ST35), “liangqiu” (ST34), and “xuehai” (SP10) acupoints were manipulated once every other day for two weeks in the fire needling acupuncture group. Mechanical withdrawal threshold and weight distribution were evaluated for behavioral testing in each group. The synovial morphology was monitored by HE staining. Pathological morphology was observed by HE staining, Saf-O staining, and toluidine blue staining. The polarization of macrophages in synovial tissue was detected using immunofluorescence (F4/80, CD86, and CD206). Results Fire needling acupuncture increased the percentage weight-bearing difference and the mechanical withdrawal threshold, and improved synovial inflammation and cartilage damage in MIA-induced KOA mice. F4/80 and CD86 expression were downregulated by fire needling acupuncture, but CD206 was increased. Conclusion Fire needling acupuncture decreases pain behaviors in KOA mice and improves synovial membrane injury and pathological cartilage damage. The macrophage polarization is involved in the mechanism of fire needling acupuncture’s amelioration of articular cartilage damage.

Acupuncture is commonly used as a treatment for migraines. Animal studies have suggested that acupuncture can decrease neuropeptides, immune cells, and proinflammatory and excitatory neurotransmitters, which are associated with the pathogenesis of neuroinflammation. In addition, acupuncture participates in the development of peripheral and central sensitization through modulation of the release of neuronal-sensitization-related mediators (brain-derived neurotrophic factor, glutamate), endocannabinoid system, and serotonin system activation. Clinical studies have demonstrated that acupuncture may be a beneficial migraine treatment, particularly in decreasing pain intensity, duration, emotional comorbidity, and days of acute medication intake. However, specific clinical effectiveness has not been substantiated, and the mechanisms underlying its efficacy remain obscure. With the development of biomedical and neuroimaging techniques, the neural mechanism of acupuncture in migraine has gained increasing attention. Neuroimaging studies have indicated that acupuncture may alter the abnormal functional activity and connectivity of the descending pain modulatory system, default mode network, thalamus, frontal-parietal network, occipital-temporal network, and cerebellum. Acupuncture may reduce neuroinflammation, regulate peripheral and central sensitization, and normalize abnormal brain activity, thereby preventing pain signal transmission. To summarize the effects and neural mechanisms of acupuncture in migraine, we performed a systematic review of literature about migraine and acupuncture. We summarized the characteristics of current clinical studies, including the types of participants, study designs, and clinical outcomes. The published findings from basic neuroimaging studies support the hypothesis that acupuncture alters abnormal neuroplasticity and brain activity. The benefits of acupuncture require further investigation through basic and clinical studies.