Effects of ligustolide on lung tissue damage in mouse of lipopolysaccharide-induced acute lung injury
Objective To study the effect of ligustilide regulating stimulator of interferon genes(STING)/Tank-binding kinase 1(TBK1)/nuclear factor-κB(NF-κB)signaling on lung tissue damage in mouse model of lipopolysaccharide(LPS)-induced acute lung injury.Methods Mice were divided into control group,model group(LPS lung injury mouse model),experimental-L group(LPS lung injury mouse model,20 mg·kg-1 ligustilide treatment),experimental-M group(LPS lung injury mouse model,60 mg·kg-1 ligustilide treatment),experimental-H group(LPS lung injury mouse model,100 mg·kg-1 ligustilide treatment),DMXAA group(LPS lung injury mouse model,100 mg·kg-1 ligustilide,STING signal agonist DMXAA treatment),Western blot was used to detect the STING,p-TBK1,TBK1,p-p65,p65 protein expression,bicinchoninic acid(BCA)method was used to detect total protein in bronchoalveolar lavage fluid,Swiss Giemsa staining was used to count the number of inflammatory cells in bronchoalveolar lavage fluid,the content of tumor necrosis factor-alpha(TNF-α)was detected by enzyme-linked immunosorbent assay(ELISA),and the content of malondialdehyde(MDA)in lung tissue was detected by thiobarbituric acid method.Results The relative expression levels of STING protein in the control,model,experimental-L,experimental-M,experimental-H groups,and DMXAA group were 0.13±0.03,0.46±0.02,0.36±0.04,0.27±0.02,0.20±0.03 and 0.38±0.04,p-TBK1/TBK1 protein ratios were 0.15±0.02,0.56±0.02,0.43±0.01,0.31±0.01,0.20±0.02 and 0.30±0.02,p-p65/p65 protein ratios were 0.24±0.01,0.66±0.03,0.41±0.02,0.32±0.04,0.22±0.02 and 0.42±0.03,the total protein contents in bronchoalveolar lavage fluid were(173.79±15.44),(304.21±19.29),(243.59±17.60),(212.51±18.24),(187.11±11.59)and(241.69±30.12)μg·mL-1;the number of macrophages were(0.11±0.02)×108,(0.94±0.09)×108,(0.72±0.08)×108,(0.57±0.04)×108,(0.41±0.04)×108 and(0.71±0.08)×108 cell·mL-1.The difference of the above indicators between model group and control group were all statistically significant(all P<0.05);the difference between experimental-L,experimental-M,experimental-H groups and model group were all statistically significant(all P<0.05);there were statistically significant difference between DMXAA group and experimental-H group(all P<0.05).Conclusion Ligustolide inhibits STING/TBK1/NF-κB signaling to alleviate lung tissue damage in a mouse model of LPS-induced acute lung injury.