Acupuncture alleviates inflammatory pain by activating CXCL1/CXCR2 signaling in the primary somatosensory cortex in adjuvant induced arthritis rats. / S1脑区CXCL1/CXCR2å‚ä¸Žé’ˆåˆºæ”¹å–„ä½å‰‚æ€§å ³èŠ‚ç‚Žå¤§é¼ ç‚Žæ€§ç—›çš„ä½œç”¨æœºåˆ¶.

OBJECTIVES: To observe whether acupuncture up-regulates chemokine CXC ligand 1 (CXCL1) in the brain to play an analgesic role through CXCL1/chemokine CXC receptor 2 (CXCR2) signaling in adjuvant induced arthritis (AIA) rats, so as to reveal its neuro-immunological mechanism underlying improvement of AIA. METHODS: BALB/c mice with relatively stable thermal pain reaction were subjected to planta injection of complete Freund adjuvant (CFA) for establishing AIA model, followed by dividing the AIA mice into simple AF750 (fluorochrome) and AF750+CXCL1 groups (n=2 in each group). AF750 labeled CXCL1 recombinant protein was then injected into the mouse's tail vein to induce elevation of CXCL1 level in blood for simulating the effect of acupuncture stimulation which has been demonstrated by our past study. In vivo small animal imaging technology was used to observe the AF750 and AF750+CXCL1-labelled target regions. After thermal pain screening, the Wistar rats with stable pain reaction were subjected to AIA modeling by injecting CFA into the rat's right planta, then were randomized into model and manual acupuncture groups (n=12 in each group). Other 12 rats that received planta injection of saline were used as the control group. Manual acupuncture (uniform reinforcing and reducing manipulations) was applied to bilateral "Zusanli" (ST36) for 4×2 min, with an interval of 5 min between every 2 min, once daily for 7 days. The thermal pain threshold was assessed by detecting the paw withdrawal latency (PWL) using a thermal pain detector. The contents of CXCL1 in the primary somatosensory cortex (S1), medial prefrontal cortex, nucleus accumbens, amygdala, periaqueductal gray and rostroventromedial medulla regions were assayed by using ELISA, and the expression levels of CXCL1, CXCR2 and mu-opioid receptor (MOR) mRNA in the S1 region were detected using real time-quantitative polymerase chain reaction. The immune-fluorescence positive cellular rate of CXCL1 and CXCR2 in S1 region was observed after immunofluorescence stain. The immunofluorescence double-stain of CXCR2 and astrocyte marker glial fibrillary acidic protein (GFAP) or neuron marker NeuN or MOR was used to determine whether there is a co-expression between them. RESULTS: In AIA mice, results of in vivo experiments showed no obvious enrichment signal of AF750 or AF750+CXCL1 in any organ of the body, while in vitro experiments showed that there was a stronger fluorescence signal of CXCL1 recombinant protein in the brain. In rats, compared with the control group, the PWL from day 0 to day 7 was significantly decreased (P<0.01) and the expression of CXCR2 mRNA in the S1 region significantly increased in the model group (P<0.05), while in comparison with the model group, the PWL from day 2 to day 7, CXCL1 content, CXCR2 mRNA expression and CXCR2 content, and MOR mRNA expression in the S1 region were significantly increased in the manual acupuncture group (P<0.05, P<0.01). Immunofluorescence stain showed that CXCR2 co-stained with NeuN and MOR in the S1 region, indicating that CXCR2 exists in neurons and MOR-positive neurons but not in GFAP positive astrocytes. CONCLUSIONS: Acupuncture can increase the content of CXCL1 in S1 region, up-regulate CXCR2 on neurons in the S1 region and improve MOR expression in S1 region of AIA rats, which may contribute to its effect in alleviating inflammatory pain.

[Current situation and prospect of researches on regularities and mechanisms of acupuncture-moxibustion in alleviating chronic inflammatory response].

The inflammatory response plays an important role in the onset, development and prognosis of inflammatory diseases and a variety of chronic diseases. Long-term uncontrolled inflammatory response may lead to dysfunction or loss of organ tissue function. Clinical practice and evidence-based medicine suggest that acupuncture can effectively alleviate the inflammatory status of various inflammatory diseases and chronic diseases. Stimulation of acupoints related to internal organs and target organs can initiate neuromodulation by modulating the microenvironment of acupoints. After integration of acupuncture stimulus information in the central nervous system, neurotransmitters, hormones, etc. are released and ultimately act on immune cells through neuro-endocrine-immune pathways, such as the vagus-mediated cholinergic anti-inflammatory pathway, vagus nerve-adrenal medullary-dopamine pathway, somatic sympathetic nerve pathway, and hypothalamic-pituitary-adrenal axis, etc. Ultimately, the intracellular signaling pathways and polarization balance of monocytes/macrophages and T cell subsets are regulated and the immune homeo-stasis of target organs of the body realizes. Therefore, we proposed that the anti-inflammatory action of acupuncture may be one of the universal therapeutic strategies for multiple diseases, and a powerful interpretation of acupuncture in regulating the balance of yin and yang. The elucidation of its anti-inflammatory action rules and mechanism may better realize the clinical transformation of acupuncture and moxibustion precision treatment.

The autonomic nervous system: A potential link to the efficacy of acupuncture.

The autonomic nervous system (ANS) is a diffuse network that regulates physiological systems to maintain body homeostasis by integrating inputs from the internal and external environment, including the sympathetic, parasympathetic, and enteric nervous systems (ENS). Recent evidence suggests that ANS is one of the key neural pathways for acupuncture signal transduction, which has attracted worldwide attention in the acupuncture field. Here, we reviewed the basic and clinical research published in PubMed over the past 20 years on the effects of acupuncture on ANS regulation and homeostasis maintenance. It was found that acupuncture effectively alleviates ANS dysfunction-associated symptoms in its indications, such as migraine, depression, insomnia, functional dyspepsia, functional constipation. Acupuncture stimulation on some specific acupoints activates sensory nerve fibers, the spinal cord, and the brain. Using information integration and efferents from a complex network of autonomic nuclei of the brain, such as the insular cortex (IC), prefrontal cortex, anterior cingulate cortex (ACC), amygdala (AMG), hypothalamus, periaqueductal gray (PAG), nucleus tractus solitarius (NTS), ventrolateral medulla (VLM), nucleus ambiguus (AMB), acupuncture alleviates visceral dysfunction, inflammation via efferent autonomic nerves, and relieves pain and pain affect. The modulating pattern of sympathetic and parasympathetic nerves is associated with acupuncture stimulation on specific acupoints, intervention parameters, and disease models, and the relationships among them require further exploration. In conclusion, ANS is one of the therapeutic targets for acupuncture and mediates acupuncture's actions, which restores homeostasis. A systemic study is needed to determine the rules and mechanisms underlying the effects of acupoint stimulation on corresponding organs mediated by specific central nervous networks and the efferent ANS.

[Acupoit is the "transducer" in the physiochemical information coupling response of acupuncture].

Acupoint is the initial response site of acupuncture stimulus and also the source link of the effect onset of acupuncture. Acupuncture is a mechanical physical stimulus. How is the mechanical force of acupuncture transduced into neuroelectrical and biochemical signals at acupoint? How does the physiochemical information of acupoint launch acupuncture effect? All of these remain the common and crucial questions in the study of acupuncture effect mechanism. Physical changes are induced in the local tissue of acupoint by needling techniques, such as the deformation and displacement of muscle fibers, which may act on the nerve ending receptors and produce electroneurographic signals. Besides, these changes may activate the mechanosensitive ion channels of the cytomembrane in acupoint site. Through cellular signal transduction, the physical signals may be transformed into chemical ones to trigger the physiochemical coupling response of acupoint microenvironment. Eventually, acupuncture effect is generated via nerves and body fluids. "The mechanical force of acupuncture", through "the physiochemical transduction", promotes the body's perception and transmits acupuncture signals. It suggests that acupoint is the "transducer" in the physiochemical information coupling response of acupuncture.