ABSTRACT
The present study investigated the effect of active components of Descurainia sophia on allergic asthma and explored the underlying mechanism. SD male rats were randomly divided into a normal group(NC), a model group(M), a D. sophia decoction group(DS), a D. sophia fatty oil group(FO), a D. sophia flavonoid glycoside group(FG), a D. sophia oligosaccharide group(Oli), and a positive drug dexamethasone group(Y). The allergic asthma model was induced in rats by intraperitoneal injection of ovalbumin(OVA) and aluminum hydroxide gel adjuvant(sensitization) and atomization of OVA solution(excitation). After modeling, asthma-related indicators, tracheal phenol red excretion, inflammatory cell levels in the peripheral blood, lung permeability index(LPI), and oxygenation index(OI) of rats were detected. The pathological changes of lung tissues were observed by HE staining. Enzyme-linked immunosorbent assay(ELISA) was used to detect the content of inflammatory factors immunoglobulin E(IgE), interleukin-4(IL-4), and interferon-γ(IFN-γ) in the bronchoalveolar lavage fluid(BALF) and the content of endothelin-1(ET-1) and angiotensin-converting enzyme(ACE) in lung tissue homogenate. The serum content of nitric oxide(NO) was detected by colorimetry. Western blot was employed to determine the protein expression of Toll-like receptor 4(TLR4), nuclear factor κB-p65(NF-κB-p65), phosphorylated NF-κB-p65(p-NF-κB-p65), myosin light chain kinase(MLCK), vascular endothelial cadherin(VE cadherin), connexin 43, and claudin 5, and the mechanism of active components of D. sophia on allergic asthma was explored. As revealed by the results, the M group showed extensive infiltration of inflammatory cells around the bronchus of the lung tissues of the allergic asthma rats, thickened bronchial wall, severely deformed alveolar structure, increased number of wheezes, the content of IgE, IL-4, ET-1, and ACE, inflammatory cells, and LPI, and reduced latency of asthma, tracheal phenol red excretion, IFN-γ, NO content, and OI. After the intervention of the active components of D. sophia, the DS, FO, FG, Oli, and Y groups showed improved asthma-related indicators, tracheal phenol red excretion, and lung tissue lesions in allergic asthma rats, and the effects in the FO and Oli groups were superior. The content of inflammatory factors in BALF was recovered in the DS, FO, and Y groups and the FG and Oli groups. The number of inflammatory cells in rats was reduced in the DS and FO groups, and the FG, Oli, and Y groups to varying degrees, and the effect in the FO group was superior. DS, FO, Oli, and Y reduced ET-1, ACE, and LPI and increased NO and OI. FG recovered NO, ET-1, ACE, LPI, and OI to improve lung epithelial damage and permeability. Further investigation of inflammation-related TLR4/NF-κB pathways, MLCK, and related skeleton protein levels showed that TLR4, NF-κB-p65, p-NF-κB-p65, and MLCK levels were increased, and VE cadherin, connexin 43, and claudin 5 were reduced in the M group. DS, FO, FG, Oli, and Y could reduce the protein expression related to the TLR4 pathway to varying degrees, and regulate the protein expression of MLCK, VE cadherin, connexin 43, and claudin 5. It is inferred that the active components of D. sophia improve lung permeability in rats with allergic asthma presumedly by regulating the TLR4/NF-κB signaling pathway to improve airway inflammation, mediating MLCK and connexin, and regulating epithelial damage.