Study On Microecological Changes Of Pulmonary Microecology In Rats With COPD Model Under Low Temperature Stress

Objective:To explore the microecology and molecular immunological changes of lung microecology and lung tissue in COPD rats under the stress of temperature difference.Method:1.to establish animal model of SD rat COPD,using smoked a joint lipopolysaccharide endotracheal drip build experimental groups: normal control group（21℃）at room temperature COPD made module（5℃）in low temperature COPD module2.ELISA method to detect the normal control group and related inflammatory cytokines in serum of rats after building the expression level and HE staining to observe the lung tissue pathology change3.16 SrDNA sequencing amplification: for each lung tissue of rats after grinding homogenate,total bacterial genome DNA extracted,using 16 SrDNA of PCR amplification,purification and build library,the HiSeq 2500 PE250 platform sequencing analysis,the results are species annotation classification clustering diversity analysis variance analysis function prediction and the flora bioinformatics analysis correlation analysis to compare related inflammatory factors such as the relationship between the bacterial flora changes with lungs Result:1.The results of serum inflammatory factors in rats showed that the levels of serum IL-1β and TNF-α in COPD model group were significantly higher than those in normal control group（P<0.05）;The expression of IL-6 was not significantly different between the normal control group and the COPD model group（p>0.05）.2.The results of semi-quantitative analysis of lung pathology in COPD rats showed that the MAN of the COPD model group was lower than the normal control group,while the MLI was greater than the normal control group,there was a statistically significant difference（P<0.01 and P<0.01）.The MLI of the cryogenic model group was slightly lower than that of the room temperature modeling group,while MAN was slightly higher at the room temperature modeling group,but there was no statistical difference between the two groups（P>0.05）.3.Changes of lung microbiota in normal control group and COPD-induced model group（1）Sequencing analysis showed that the lung bacterial flora in each group was annotated to 7 phyla at the level of the phyla,mainly including Tenericutes,Proteobacteria,Bacteroidetes,and Thick-walled bacteria.Fermiutes,Fusobacteria,and abundance of Actinobacteria,Cyanobacteria,and other unknown bacteria with unknown status（Bacteria: Other）.（2）A total of 10 genus were annotated at the taxonomic level,mainly including: Mycoplasma,Vibrio,Filobacterium,low abundance Bacteroides,and Streptococcus Streptobacillus,Acinetobacter,Prevotella₉,Bordetella,Exiguobacterium,Boechera_gunnisoniana,Unknown bacteria（Bacteria: Other）.（3）At the phyla level,the relative abundance of Tenericutes,Actinobacteria,and Fusobacteria in the COPD model group was significantly lower than that in the normal control group（p<0.05）.The relative abundance of Proteobacteria was significantly increased（p<0.00）;at the genus level,the relative abundance of Mycoplasma was lower than that of the normal control group（p<0.05）,while Vibrio and Bacteroides The relative abundance of genus Bacteroides was significantly higher than that of normal controls（p<0.01）.（4）Alpha diversity analysis indicated that the microbial diversity in the normal control group was significantly lower than that in the room temperature modeling group and the low temperature modeling group（p<0.01）,and the flora diversity in the room temperature modeling group was also lower than that in the low temperature modeling group.The difference was not statistically significant（p>0.05）.（5）Beta diversity analysis suggested that there was a difference in the composition of lung tissue between the model group and the normal control group.The difference between the lung tissue structure of the low temperature model group and the normal control group was the most obvious.（6）In the analysis of species diversity,the genus annotated with specificity of the species in the normal control group was Pseudomonas genus,while the genus of species with annotated specificity in the low temperature model group was genus of fiobacterium and sphingobacteriia.（7）The Pathway annotation of microbial function predicts the metabolic pathways of apoptosis and pathways related to carbohydrates,pyrimidine biosynthesis,amino-tRNA biosynthesis,oxidative phosphorylation metabolism,and energy metabolism.Conclusion:1.The expression of IL-6 and TNF-α in the serum of the COPD model was higher than that in the healthy control group,indicating that IL-6 tnf-alpha was involved in the airway inflammation of COPD and had a certain pro-inflammatory effect.2.COPD model of rat lung tissue flora diversity and composition and normal healthy rats exists obvious difference in low temperature under the condition of COPD model rat lung flora structure imbalance,low temperature stress can cause COPD rat lung micro ecological environment change.