Exploring the Mechanism of Anti-asthma Effect of Fujiu Patch on Modulation of Th17/Treg Immune Balance Based on IL-6/STAT3 and IL-2/STAT5 Signaling Pathways / 中药新药与临床药理

ABSTRACT

Objective This study aims to investigate the regulatory effects of Fujiu Patch(composed of Sinapis Semen,Kansui Radix,Corydalis Rhizoma and Asari Radix et Rhizoma)on the CD4+ T helper 17 cell(Th17)/CD4+CD25+ regulatory T cell(Treg)balance in asthmatic rats via the signal pathway of IL-6/signal transducer and activator of transcription 3(STAT3)as well as IL-2/signal transducer and activator of transcription 5(STAT5),and to reveal its anti-asthma mechanisms.Methods An experimental asthma model was constructed by ovalbumin(OVA)combined with aluminum hydroxide sensitization and challenge,and then the rats were administered with Fujiu Patch at Dazhui(DU14),Feishu(BL13)and Shenshu(BL23)points for 4 hours each time,once every other day for 7 times.Immunohistochemistry was used to detect the positive expressions of Th17 specific cytokine(IL-17)and Treg transcription factor(Foxp3)in rat lung tissue.The percentage of Th17 and Treg cells in peripheral blood was examined by flow cytometry analysis,and the expressions of IL-6/STAT3 and IL-2/STAT5 pathway-related proteins in lung tissue were assayed with Western Blot.Results Compared to the model group,IL-17 positive expression in the rat lung showed a significant reduction in the Fujiu Patch group(P＜0.01),while the positive expression of Foxp3 was obviously increased(P＜0.05).Meanwhile,the protein expression levels of IL-6 and phospho-STAT3 were were significantly declined(P＜0.01),and the protein expression levels of IL-2 and phospho-STAT5 were were significantly elevated(P＜0.01).However,there was no significant alteration in the total protein expressions of STAT3 and STAT5(P＞0.05).Furthermore,the proportion of Th17 cells in peripheral blood of rats in the Fujiu Patch group was lower than that in the model group,while the proportion of Treg cells was higher than that in the model group.Statistically-significant differences were observed(all P＜0.01).Conclusion These findings indicate that Th17/Treg immune imbalance occurs in asthmatic rat.Fujiu Patch may exert anti-asthma effects via inhibiting the expression of IL-6,downregulating the expression of phospho-STAT3,diminishing the level of IL-17-producing Th17 cells,as well as increasing the expressions of IL-2-mediated STAT5 phosphorylation,raising the level of Foxp3-expressing Treg cells,promoting Th17/Treg balance and suppressing immune responses in rat with asthma.