Objective: To observe the effect of acupoint injection on serum T helper (Th)1/Th2 related cytokines, and the expression levels of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88) and activator protein-1 (AP-1) of nasal mucosa in allergic rhinitis (AR) rats, so as to explore its mechanism underlying improvement of AR.
Methods: Thirty-two SD rats were randomly divided into normal, model, non-acupoint injection and acupoint injection groups (n=8 in each group). The AR model was established by ovalbumin sensitization. In the acupoint injection group, "Yintang" (GV24+) and bilateral "Yingxiang" (LI20) were selected for injection of mixture solution of dexamethasone and lidocaine (0.05 mL/acupoint), once every 4 days for a total of 4 times. The non-acupoints, located at the midpoint between the "Houhai" and "Huantiao" (GB30) on the bilateral hips and the sites 5 cm inferior to the axillary were injected with the same dose of mixture solution as that in the acupoint injection group. The AR severity was assessed by cumulative quantification scoring methods (including the numbers of nose-catching and sneezes, and the amount of nasal secretions in 30 min). The pathological changes of nasal mucosa were observed by HE staining. The contents of immunoglobulin E (IgE), interleukin (IL)-4 and interferon (IFN)-γ in serum were detected by ELISA. The expressions of TLR4 and MyD88 in nasal mucosa was detected by immunofluorescence. The expression of AP-1 in nasal mucosa was detected by Western blot.
Results: Following modeling, the AR symptom score, serum IgE and IL-4 contents and expression of TLR4, MyD88 and AP-1 of nasal mucosa were significantly increased in the model group than those in the normal group (P<0.01), while the serum IFN-γ content was significantly decreased (P<0.01). Compared with the model group and non-acupoint injection group, the AR symptom score, the serum contents of IgE and IL-4 and the expressions of TLR4, MyD88 and AP-1 in nasal mucosa were significantly decreased in the acupoint injection group (P<0.01, P<0.05), while the serum IFN-γ content was significantly increased (P<0.01). H.E. staining of the nasal mucosa showed that most of the epithelium fell off, the lamina propria vessels expanded, the glands proliferated, and eosinophils and lymphocytes infiltrated in the model and non-acupoint injection groups, and those were significantly improved in the acupoint injection group.
Conclusion: Acupoint injection can effectively improve allergic inflammation of the nose in AR rats, which may be related with its function in inhibiting the abnormal activation of TLR4/AP-1 signaling pathway and regulating the imbalance of Th1/Th2.
目的：观察穴位注射对变应性鼻炎(AR)大鼠血清辅助性T细胞（Th）1/Th2相关细胞因子及鼻黏膜Toll样受体4(TLR4)、髓样分化因子88(MyD88)、激活蛋白-1(AP-1)表达水平的影响，探讨穴位注射治疗AR的作用机制。方法：SD大鼠随机分为正常组、模型组、非经非穴组、穴位注射组，每组8只。用卵清蛋白致敏法建立AR大鼠模型。穴位注射组给予地塞米松和利多卡因混合液注射双侧“迎香”和“印堂”，非经非穴组给予地塞米松和利多卡因混合液注射非经非穴处，两组均每4日治疗1次，共4次。对各组大鼠症状积分进行评定；HE染色法观察鼻黏膜组织病理形态学变化；ELISA法检测血清免疫球蛋白E(IgE)、白细胞介素(IL)-4和干扰素(IFN)-γ含量；免疫荧光染色法检测鼻黏膜组织TLR4、MyD88的表达；Western blot法检测鼻黏膜组织AP-1的表达。结果：与正常组比较，模型组症状积分显著升高(P<0.01)，血清IgE、IL-4含量及鼻黏膜TLR4、MyD88、AP-1表达均显著升高(P<0.01)，血清IFN-γ含量显著降低(P<0.01)。与模型组和非经非穴组比较，穴位注射组症状积分显著降低(P<0.01)，血清IgE、IL-4含量及鼻黏膜TLR4、MyD88、AP-1表达均显著降低(P<0.01，P<0.05)，血清IFN-γ含量显著升高(P<0.01)。模型组和非经非穴组可见鼻黏膜上皮大部分脱落，固有层血管扩张，腺体增生，伴有嗜酸性粒细胞和淋巴细胞浸润；穴位注射组上皮病变、腺体增生和炎性反应明显减轻。结论：穴位注射可有效改善AR大鼠鼻部过敏性炎性反应，其机制可能与抑制炎性信号通路TLR4/AP-1的异常激活，进而调节Th1/Th2细胞平衡有关。.
Keywords: Acupoint injection; Allergic rhinitis; Th1/Th2 cytokines; Toll-like receptor 4/activator protein-1 pathway.