This study investigated the effect of Maxing Shigan Decoction(MXSGD) and its disassembled prescriptions against the airway inflammation in respiratory syncytial virus(RSV)-aggravated asthma and the regulation of transient receptor potential vanilloid-1(TRPV1). To be specific, ovalbumin(OVA) and RSV were used to induce aggravated asthma in mice(female, C57BL/6). Then the model mice were intervened by MXSGD and the disassembled prescriptions. The eosinophil(EOS) in peripheral blood, inflammatory cells in bronchoalveolar lavage fluid(BALF), enhanced pause(Penh) variation, and lung pathological damage in each group were observed, and the changes of interleukin(IL)-4, IL-13, substance P(SP), and prostaglandin E2(PGE2) in BALF were mea-sured by enzyme-linked immunosorbent assay(ELISA). Quantitative real time polymerase chain reaction(qPCR) and Western blot were used to detect mRNA and protein of TRPV1 in mouse lung tissue. In the in vitro experiment, 16 HBE cells were stimulated with IL-4 and RSV. Then the changes of TRPV1 expression after the intervention with the serum containing MXSGD and its disassembled prescriptions were observed. Besides, the intracellular Ca~(2+) level after the stimulation with TRPV1 agonist was evaluated. The results showed that the mice in the model group had obvious asthma phenotype, the levels of various inflammatory cells in the peripheral blood and BALF and Penh were significantly increased(P<0.05, P<0.01), and the lung tissue was severely damaged compared with the control group. Compared with the model group, the levels of EOS in the peripheral blood and BALF were significantly decreased in the MXSGD group, the SG group and the MXC group(P<0.05, P<0.01). The levels of WBC and neutrophils in BALF were significantly decreased in the MXSGD group and SG group(P<0.01), the levels of neutrophils in BALF were decreased in the MXC group(P<0.05). The improvement effect of the MXGSD on the level of inflammatory cells in peripheral blood and BALF was better than that of two disassembled groups(P<0.05, P<0.01). After 50 mg·mL~(-1) acetylcholine chloride stimulation, the Penh values of the MXSGD group and the MXC group significantly decreased(P<0.01), and the Penh value of the SG group decreased(P<0.05). The levels of IL-4, IL-13, PGE2 and SP in BALF could be significantly decreased in the MXSGD group(P<0.05, P<0.01), the levels of IL-13 and PGE2 in BALF could be decreased in the MXC group(P<0.05, P<0.01), and the levels of IL-13, PGE2 and SP in BALF could be decreased in the SG group(P<0.05, P<0.01). MXSGD could down-regulate the protein and mRNA expression of TRPV1 in lung tissue(P<0.05, P<0.01). The serum containing MXSGD and its disassembled prescriptions could down-regulate TRPV1 expression in 16 HBE cells stimulated by IL-4 combined with RSV and inhibit the inward flow of Ca~(2+) induced by TRPV1 agonist, especially the serum containing MXSGD which showed better effect than the serum containing disassembled ones(P<0.05). In vivo and in vitro experiments verified the protective effect of MXSGD and its disassembled prescriptions against airway inflammation in RSV-exacerbated asthma, the whole decoction thus possessed synergy in treating asthma, with better performance than the dissembled prescriptions. Different groups of prescription had made contributions in improving airway hyperresponsiveness, anti-allergy and anti-inflammation. The mechanism is the likelihood that it regulates TRPV1 channel and levels of related inflammatory mediators.
Keywords: Maxing Shigan Decoction; TRPV1; bronchial asthma; relieving dyspnea; respiratory syncytial virus.