ABSTRACT
ObjectiveTo investigate the protective effect and mechanism of Euphorbia helioscopia aqueous extract （EHE） on mice with chronic obstructive pulmonary disease （COPD） and its influence on precancerous lesion-associated proteins in lung tissues induced by cigarette smoke （CS）. MethodThe COPD model was induced by CS in 60 mice and the model mice were randomly divided into control group， model group， positive drug group （dexamethasone， 2 mg·kg-1）， and low-， medium-， and high-dose EHE groups （1.875， 3.75， 7.5 g·kg-1）. The high-performance liquid chromatography （HPLC） method was used to determine the related components in EHE. The changes in end-expiratory pause （EEP）， airway resistance （Penh）， expiratory flow at 50% vital capacity （EF50）， and other pulmonary function indexes were detected by the spirometer. The levels of inflammatory factors， such as interleukin （IL）-2， IL-5， IL-18， IL-17A， and IL-27 in bronchoalveolar lavage fluid （BALF） of mice were detected by high-throughput liquid protein chip technology. Hematoxylin-eosin （HE） staining was used to detect the pathological changes in lung tissues in mice. The content of malondialdehyde （MDA）， myeloperoxidase （MPO）， and glutathione peroxidase （GSH-Px） in lung tissues was determined by the colorimetric method. The mRNA relative expression of tumor necrosis factor-α （TNF-α）， transforming growth factor-β （TGF-β）， matrix metalloproteinase-2 （MMP-2）， matrix metalloproteinase-9 （MMP-9）， and matrix metalloproteinase-12 （MMP-12） was detected by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. Immunohistochemistry （IHC） was used to detect the expression of tumor protein （P53） and cell proliferation-associated antigen （Ki67） in lung tissues， and Western blot was used to detect the relative expression of tumor suppressor protein （P16）， DNA （cytosine-5）-methyltransferase 1 （DNMT1）， and fragile histidine triad （FHIT） in lung tissues. ResultThe results showed that the main compounds in EHE included phenols （gallic acid and protocatechuic acid） and flavonoids （such as hyperoside， rutin， myricetin， naringenin， quercetin， luteolin， kaempferol， and licorice chalcone A）， among which gallic acid and rutin were the highest in content. Compared with normal group， model group showed increased levels of EEP， EF50， and Penh （P<0.05）， and showed increased MDA and MPO levels （P<0.01） and decreased GSH-Px （P<0.01）， and the model group displayed increased levels of IL-2， IL-5， IL-18， IL-17A， IL-27， TNF-α， TGF-β， MMP-2， MMP-9， and MMP-12 （P<0.05）. And the model group exhibited up-regulated expression of P53， Ki67， and FHIT in lung tissues （P<0.01） and down-regulated expression of DNMT1 and P16 （P<0.01）. Compared with model group， the EHE groups showed decreased EEP and EF50 levels （P<0.05）. The pathological injury of lung tissues in mice of the model group was observed under HE staining， and the pathological injury of basal cell hyperplasia of lung tissues was gradually improved after treatment with EHE. The EHE groups showed reduced levels of MDA and MPO （P<0.01） and increased GSH-Px （P<0.01）. The EHE groups displayed decreased levels of IL-2， IL-5， IL-18， IL-17A， IL-27， TNF-α， TGF-β， MMP-2， MMP-9， and MMP-12 （P<0.05）. And the EHE groups showed down-regulated Ki67 and FHIT in lung tissues （P<0.05） and up-regulated expression of P53 and DNMT1 （P<0.05）. ConclusionEHE can protect mice from COPD and inhibit precancerous lesions， and the mechanism may be related to the inhibition of inflammation and oxidative stress response， regulation of protease and antiprotease imbalance， and regulation of epithelial cell growth.