[Study on effect of anemoside B4 in improving COPD rats by regulating IL-12/STAT4 and IL-4/STAT6 signaling pathways]

To study the effect of anemoside B4 on rats with chronic obstructive pulmonary disease (COPD).Seventy-two SD male rats were randomly divided into blank group and model group.The method of exposure to cigarette smoke and combined with lipopolysaccharide (LPS) was used to replicate the rat model of COPD.After the model was maintained for 5 weeks,the rats were randomly divided into model group,dexamethasone group (0.81 mg·kg~(-1)) and anemoside B4 low,medium and high (2,4,8 mg·kg~(-1)) dose groups,a group of 12 animals were administered,and then the administration was started.The administration was maintained until the28th day,and the pulmonary function parameters of rats were measured by an animal pulmonary function instrument.After testing the rat lung function parameters,immediately draw rat alveolar lavage fluid (BALF),and use high-throughput protein chip technology to determined the expression levels of inflammatory cytokines in rat BALF.HE staining was used to observe the general pathological changes of rat lung and tracheal tissue.Masson staining was used to observe the collagen deposition in rat lung tissue.Real-time q PCR method was used to determine the mRNA expression level of related genes in rat lung tissue.Western blot method was used to determine the expression levels of related proteins in rat lung tissues.According to the findings,compared with the model group,the dexamethasone group and the anemoside B4 drug groups had different degrees of increase in the lung function parameters of rats (P<0.01,P<0.05),improved the expression level of inflammatory cytokines in the BALF of rats to varying degrees (P<0.01,P<0.05),and improved the pathological structure of rat lung tissue to varying degrees.Relative mRNA expressions of matrix metalloproteinase 2 (MMP-2),matrix metalloproteinase 12 (MMP-12),matrix metalloproteinase inhibitor 1 (TIMP-1),interleukin-6 (IL-6),and transforming growth factor-β1 (TGF-β1) were significantly reduced (P<0.01);whereas relative mRNA expressions of matrix metalloproteinase 9(MMP-9) and matrix metalloproteinase inhibitor 2 (TIMP-2) were increased significantly (P<0.01).The mRNA and protein expression levels of T-box transcription factor (T-bet),interleukin-12 (IL-12) and signal transducer and activator of transcription 4(STAT4) reduced to varying degrees (P<0.01,P<0.05).The mRNA of transcription factor GATA3 (binding protein-3),interleukin-4 (IL-4) and signal transducer and activator of transcription 6 (STAT6) in rat lung tissues and the protein expression levels of IL-4 and STAT6 were increased to varying degrees (P<0.01,P<0.05).In conclusion,anemoside B4 has a certain protective effect on COPD rats caused by cigarette smoke exposure and combined with LPS.The mechanism of action may be related to the regulation of IL-12/STAT4 and IL-4/STAT6 signaling pathways.