Effects of Total Flavonoids of Scutellaria Baicalensis Georgi Improving Airway Inflammation and Its Effects on TLR3/TRIF Pathway Expression in Asthmatic Mice

SONG Zhijun; LI Jianxiong; LIN Wengui

doi:10.13730/j.issn.2097-2148.2023.11.003

Abstract：Objective To explore the effects of total flavonoids of Scutellaria baicalensis georgi on improving airway inflammation and Toll-like receptor 3(TLR3)/TIR domain-containing adaptor inducing interferon-beta(TRIF)pathway expression in asthmatic mice.Methods A total of female Balb/c mice aged 4 to 6 weeks were randomly divided into nor-mal control group,model group,positive control group(dexamethasone,1 mg/kg),total flavonoids of Scutellaria ba-icalensis georgi low-dose group(25 mg/kg)and total flavonoids of Scutellaria baicalensis georgi high-dose group(50 mg/kg),with 10 rats in each.Except the normal control group,the asthmatic mouse model was constructed in the other groups.Hematoxylin-eosin staining(HE)were used to observe the pathological changes of lung tissues of mice,and the airway remodeling of mice was analyzed according to pathological pictures;bronchial wall area/inner perimeter(W/Pi),bronchial smooth muscle area/inner perimeter(S/Pi)and smooth muscle nucleus number/inner perimeter(N/Pi)were calculated.Interleukin 6(IL-6)and IL-8 levels in bronchoalveolar lavagefluid(BALF)were detected by enzyme linked immunosorbent assay(ELISA).The mRNA expression levels of TLR3 and TRIF in lung tissues of mice were detected by quantitative real-time polymerase chain reaction(qPCR).The expression levels of TLR3 and TRIF proteins in lung tis-sues of mice were detected by Western bolt.Results The pathological results showed that the bronchial lumen and alveoli in the normal control group maintained good integrity,while the mice in the model group showed increased mucosal ede-ma,inflammatory cell infiltration(submucosa and mucosal layer)and the number of inflammatory cell infiltration in the airway wall,and decreased inflammatory cell infiltration in the bronchial lumen and alveoli after the administration of total flavonoids of Scutellaria baicalensis georgi,the number of inflammatory cells in the total flavonoids of Scutellaria baicalensis georgi high-dose group was lower than that in the low-dose group.Compared with normal control group,W/Pi,S/Pi,N/Pi,IL-6,IL-8,TLR3 and TRIF mRNA and protein levels in model groups significantly increased(all P＜0.05);compared with model group,W/Pi,S/Pi,N/Pi,IL-6,IL-8,TLR3 and TRIF mRNA and protein levels in total flavonoids of Scutellaria baicalensis georgi low-dose and high-dose groups and positive control group significantly decreased(all P＜0.05);W/Pi,S/Pi,N/Pi,IL-6,IL-8,TLR3,TRIF mRNA and protein levels in total flavonoids of Scutellaria baicalensis georgi low dose group were signifi-cantly higher than those in high dose group(all P＜0.05);there was no significant difference in all indexes between total flavonoids of Scutellaria baicalensis georgi high dose group and positive control group(P＞0.05).Conclusion Total fla-vonoids of Scutellaria baicalensis georgi can effectively improve airway inflammation in asthmatic mice,and its mechanism may be related to inhibiting TLR3/TRIF signaling pathway,reducing inflammatory response and alleviating airway remo-ving.