[Effect of moxa-cone moxibustion at lung's back- points and front- points on Th17/Treg balance in mice with asthma].

Objective: To observe the effect of moxa-cone moxibustion at lung's back- points and front- points on the expression of helper T lymphocyte 17 (Th 17)/regulatory T lymphocyte (Treg) in mice with asthma, and to explore the possible mechanism of moxa-cone moxibustion on asthma.

Methods: Sixty SPF-grade healthy male Balb/c mice were randomly divided into a normal group, a model group, an LY294002 group (LY group), an electroacupuncture (EA) group and a moxibustion group, 12 mice in each group. Asthma model was replicated by using ovalbumin (OVA) sensitization. Except the mice in the normal group, all the mice were intraperitoneally injected with sensitization solution (containing 15 μg of OVA and 30 mg of aluminum hydroxide) on the 1st day, 7th day and 14th day, 0.5 mL per mice; from the 15th day, 1% OVA solution was atomized for 20 min, once a day for 2 weeks; the mice in the normal group was treated with identical operations but with 0.9% sodium chloride solution. The mice in the LY group were treated with injection of LY294002 at tail vein on the 13th day, 14th day and 15th day. At the beginning of the 15th day, The mice in the EA group were treated with EA at "Feishu" (BL 13) and "Zhongfu" (LU 1) with disperse-dense wave, frequency of 2 Hz/20 Hz, intensity of 1 mA, 15 min each time, once a day for 2 weeks. The mice in the moxibustion group was treated with moxa-cone moxibustion at "Feishu" (BL 13) and "Zhongfu" (LU 1) from the 15th day, three moxa-cones per acupoint, once a day for 2 weeks. On the 16th day, 18th day and 22nd day, the incubation period of asthma was recorded. On the 29th day, all the samples were collected. The expressions of IL-17 and IL-10 in serum and bronchoalveolar lavage fluid (BALF) were detected by ELISA method. The pathological changes of lung tissue were observed by HE staining. The percentage of Th17, Treg and Th17/Treg ratio in spleen tissue were detected by flow cytometry method.

Results: Compared with the normal group, the incubation period of asthma in the model group was significantly shortened (<0.01), while that in the LY group, the EA group and the moxibustion group was longer than that in the model group (<0.01). After the intervention, bleeding and inflammatory exudation in the lung tissue were observed in the model group, and a large number of inflammatory cell infiltration around the bronchus and alveoli was found, and extensive consolidation appeared; the pathological changes of lung tissue in the LY group, the EA group and the moxibustion group were significantly reduced, and the structure of bronchus and alveoli was basically normal, and the inflammatory exudation and inflammatory cell infiltration were significantly reduced compared with the model group; the inflammatory reaction in the moxibustion group was slightly less than that in the LY group and the EA group. Compared with the normal group, the content of IL-17 in serum and BALF, the percentage of Th17 and Th17/Treg ratio in spleen tissue in the model group after intervention were increased (<0.01), while the content of IL-10 in serum and BALF and the percentage of Treg in spleen tissue were decreased (<0.01, <0.05). Compared with the model group, the contents of IL-17 in serum and BALF, Th17 percentage and Th17/Treg ratio in spleen tissue in the LY group, the EA group and the moxibustion group were significantly reduced (<0.01, <0.05), while the content of IL-10 in serum and BALF and the percentage of Treg in spleen tissue were increased (<0.01, <0.05). The above indice had no significant difference among all the intervention groups (>0.05).

Conclusion: The Th17/Treg is imbalanced in asthmatic body. The moxibustion at lung's back- points and front- points can control asthma by regulating Th17/Treg imbalance and restoring immune homeostasis.