To Investigate The Effect Of Qingfei Huatan Decoction On Airway Inflammation In COPD Model Rats Through TLR4/NF-κB Pathway

Objective: To create a rat model of chronic obstructive pulmonary disease(COPD)by injecting lipopolysaccharide(LPS)into rat trachea and smoking rats.After successful modeling,drug intervention was carried out respectively,and the effect of Qingfei Huatan Decoction on the inflammatory mechanism of COPD model rats was investigated from TLR4/NF-κB pathway,which provided experimental basis for the treatment of COPD with traditional Chinese medicine.Methods: Sixty SPF Wistar male rats with body weight of 200±20g were randomly divided into 6 groups with 10 rats in each group: Group A(normal group),group B(COPD model group),group C(Qingfei Huatan decoction low-dose group),group D(Qingfei Huatan decoction medium-dose group),group E(Qingfei Huatan decoction high-dose group),and group F(roxithromycin group).After 1 week of adaptive feeding,group A continued to be provided with adequate food and drinking water as a normal group,and no other treatment was done.Group B,group C,group D,group E and group F were also fed normally,and the model was made by endotracheal injection of lipopolysaccharide(LPS)combined with smoking.After the successful preparation of COPD model,they were given Qingfei Huatan decoction for gavage intervention.Finally,pathological changes of lung tissues of COPD model rats before and after drug intervention were observed by microscope.The contents of IL-18,IL-21 and TNF-α in serum and BALF were determined by ELISA.The expression levels of TLR4 and NF-κB p65 in lung tissue were determined by Western Blot.Results:1.Symptom manifestations of COPD rat model: After injection of LPS combined with smoking,the rats showed cough,shortness of breath,oral and nasal secretions,foul stool,yellow urine,greasy hair and other pathologies,which were consistent with COPD.2.Lung histopathological changes: The right lung tissues of rats were observed by optical microscope,and the results showed that except group A(blank group)did not conform to COPD pathological changes,the other groups were consistent with COPD pathological changes,and a large number of inflammatory cell infiltration was observed.Trachea and bronchus wall thickened,lumen narrow,airway mucosa epithelial cells necrosis,shedding,cilia arrangement disorder;Bulla formation of lung;Tracheal submucosal glands hyperplasia,goblet cells secreted more mucus.3.Results of drug intervention.(1)Comparison of the contents of inflammatory cytokines in serum and BALF of rats in each group: Compared with blank group,the contents of IL-18,IL-21 and TNF-α in serum and BALF of rats in model group were significantly increased,and the difference was statistically significant(P < 0.05);Compared with model group,the contents of IL-18,IL-21 and TNF-α in serum and BALF of rats in Qingfei Huatan Decoction medium and high dose groups and roxithromycin group were decreased(P < 0.05).Except the content of IL-21 in serum in Qingfei Huatan decoction low dose group was similar to that in group B.The contents of IL-18,TNF-α in serum and IL-21,TNF-α in BALF were decreased,and the difference was statistically significant(P < 0.05).(2)Comparison of TLR4 and NF-κB p65 protein levels in lung tissue of rats in each group: Compared with blank group,TLR4 and NF-κB p65 protein expression levels in lung tissue of rats in model group were significantly increased,and the difference was statistically significant(P < 0.05);Compared with model group,the relative expression level of TLR4 protein in lung tissues of Qingfei Huatan decoction low-dose and medium-dose groups was similar,with no statistical significance(P > 0.05),while the relative expression level of TLR4 protein in lung tissues of Qingfei Huatan decoction high-dose group and roxithromycin group was decreased,with statistical significance(P < 0.05).Compared with model group,the relative expression level of NF-κB p65 protein in lung tissue of rats in Qingfei Huatan decoction low-dose group was similar,and the difference was not statistically significant(P > 0.05),while the relative expression level of NF-κB p65 protein in lung tissue of rats in Qingfei Huatan decoction medium-dose group was decreased,and the difference was statistically significant(P < 0.05).The relative expression level of NF-κB p65 protein in lung tissues of rats in Qingfei Huatan decoction high-dose group and roxithromycin group was decreased,the difference was statistically significant(P < 0.05),and the content of Qingfei Huatan decoction high-dose group and roxithromycin group was similar,higher than that in Qingfei huatan decoction mid-dose group,but there was no statistical significance between Qingfei Huatan decoction high-dose group and roxithromycin group(P > 0.05).Conclusion:Qingfei Huatan Decoction can reduce the inflammatory response of airway and lung tissue of COPD model rats,and its mechanism may be through regulating TLR4/NF-κB signaling pathway to reduce the content of IL-18,IL-21,TNF-α inflammatory factors in serum and BALF of COPD model rats to achieve anti-inflammatory effect,so as to achieve the purpose of treating COPD.