Protective effect and mechanism of silymarin on bronchiolitis caused by respiratory syncytial virus in mice
10.3760/cma.j.cn431274-20221116-01183
- VernacularTitle:水飞蓟素对呼吸道合胞病毒诱导毛细支气管炎小鼠的保护作用及机制
- Author:
Nan ZHANG
1
;
Qinquan ZHU
;
Weixing HE
;
Bo LI
;
Yanhong LIAO
Author Information
1. 湖南中医药大学第一附属医院儿科，长沙 410007
- Keywords:
Silybin;
Bronchiolitis;
Respiratory syncytial viruses;
Toll-like receptor 4;
NF-kappa B
- From:
Journal of Chinese Physician
2023;25(10):1477-1483
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the protective effect and mechanism of silymarin on bronchiolitis caused by respiratory syncytial virus (RSV) in mice.Methods:A mouse model of bronchiolitis was established by intranasal instillation of RSV. After successful modeling, the mice were randomly divided into a model group, a positive control group (ribavirin, 10 mg/kg), a low-dose silymarin group (25 mg/kg), a medium-dose silymarin group (50 mg/kg), and a high-dose silymarin group (100 mg/kg). In addition, a control group was established, with 12 mice in each group. The pulmonary index and RSV virus load were determined in each group of mice. Hematoxylin-eosin (HE) staining was used to observe the pathological changes in the lungs. The levels of interleukin-4 (IL-4), interferon-γ (IFN-γ), transforming growth factor-β (TGF-β), IL-17, and IL-10 in bronchoalveolar lavage fluid (BALF) were detected by enzyme-linked immunosorbent assay (ELISA). Flow cytometry was used to detect the proportion of helper T cells 17 (Th17) and regulatory T cells (Treg) in peripheral blood. Western blot was used to detect the expression levels of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), nuclear factor κB subunit p65 (NF-κB p65), and phosphorylated nuclear protein p-NF-κB p65 in lung tissue.Results:Compared with the model group, the pulmonary injury and inflammatory response were significantly improved in the medium-and high-dose silymarin groups. The pulmonary indexes were (1.27±0.17)% and (0.94±0.10)%, respectively, and the RSV virus loads were (2.65±0.19) and (2.13±0.14), respectively, which were significantly lower than those in the model group (all P<0.05). The proportion of Th17 cells in peripheral blood was (4.47±0.19)% and (3.52±0.13)%, respectively, which was significantly lower than that in the model group (all P<0.05), while the proportion of Treg cells in peripheral blood was (0.88±0.08)% and (1.33±0.12)%, respectively, which was significantly higher than that in the model group (all P<0.05). The expression levels of IL-4 and IL-17 in BALF and the protein expression levels of TLR4/NF-κB signaling pathway related proteins in lung tissue were significantly lower than those in the model group (all P<0.05), while the expression levels of IFN-γ, TGF-β, and IL-10 in BALF were significantly higher than those in the model group (all P<0.05). Conclusions:Silymarin can regulate immune function and inhibit inflammatory response, thereby improving airway inflammation in bronchiolitis mice. The mechanism may be related to inhibit activation of TLR4/NF-κB signaling pathway.
