Exploring The Possible Mechanism Of Hypoxia Training On The Regulation Of Liver Glucose Metabolism And Inflammation In Obese Mice Based On The Transcriptome

PurposeThere is excessive lipid accumulation in obese body,which is often accompanied by the disorder of glucose metabolism and chronic inflammation.Hypoxic training can improve the body’s glucose metabolism and inflammation while reducing body weight.The liver is an important place for the body to carry out glucose metabolism,and also is one of the target organs of many inflammatory factors,but there are few studies on the regulation of liver glucose metabolism and inflammation by hypoxic training,and the mechanism of its regulation is still unclear.The purpose of this study was to analyze the expression of the differential genes about glycometabolism and inflammation in the liver of the obese mice by transcriptome sequencing,and we can further explore the potentional mechanism about glycometabolism and inflammation of the obese mice.MethodsTwenty-eight SPF male C57BL/6J mice were selected,aged 6 weeks.The mice were fed in separate cages and could drink and eat freely.Mice were randomly divided into two groups: normal diet Control group(Control,Con,n=8)and high-fat diet-induced obesity(HFD,n=20).The feeding time was 8 weeks,and the mice were weighed and recorded at fixed time every week.The body weight of HFD group was20% higher than CD group.After the modeling was successful,mice in HFD group were divided into diet-induced obese control group(diet-induced obese,DIO,n=10)and Hypoxia training group(HT,n=10)by random method.After that,mice in each group were kept on the original high-fat diet,weighed and recorded at a fixed time every week.Experimental intervention program for each group of mice: Hypoxic training group: placed the mices in the hypoxic environment set by the TSE Pheno Master hypoxic metabolism chamber from 8:00 to 16:00 every day for 8 hours,6 days/week,oxygen The concentration is 14.4%,and the oxygen partial pressure is110 mm Hg.Mice were placed on a treadmill for an hour every night,running at a speed of 6m/min for the first 5 minutes,and then increase by 1m/min every 2 minutes,and the speed will gradually increase to 15m/min,the mice were asked to run until they were exhausted at the last time.The standard of exhaustion is: electric shock mice for more than 10 seconds and they still stay in place.The normal diet group and the obesity group did not have any intervention.Three days before the start of the formal experiment,all mice in the hypoxia training group need to undergo hypoxia adaptation and treadmill adaptation.The intervention time is 11 weeks.After the 11-week intervention,the mice were sacrificed to collect samples,including liver and epididymal white adipose tissue,inguinal white adipose tissue,and peri-renal white adipose tissue.The differentially expressed genes in liver tissues were screened by transcriptome sequencing technology,and then the accuracy of transcriptome analysis results was verified by q PCR assayResults(1)Establishment of obese mice modelMice were fed on high-fat diet for 8 weeks,the body weight,Body fat ratio and fasting blood glucose in HFD group(p<0.001)were increased significantly than CD group,and the average body weight in HFD group was 20% higher than that in CD group;HE staining of adipose tissue showed a significant increase in the number and volume of fat droplets,indicating that the obese mice model were successful establishment.(2)Changes of phenotype and exercise ability of obese mice after hypoxic training interventionDuring the 11-week hypoxic intervention period,the body weight in the DIO group was going up gradually,and conversely,the body weight in the HT group is going down gradually;after 11 weeks,the maximum exhaust speed and the exhaust distance in the HT(p<0.01)group were hightre obviously than the DIO(p<0.01)group;The body weight,liver weight,visceral fat weight,content of body fat and lean body mass of the HT(p<0.01)group obviously than the DIO(p<0.01)group.The content of adipose tissue(white adipose tissue in groin,epididymis and perirenal white adipose tissue)was also significantly decreased than that in DIO group(p<0.01).(3)Screening and analysis of differentially expressed genesThe total number of genes that we have got was 31909 by transcriptome sequencing technology,among which,compared with the DIO group,the number of up-regulated genes in the HT(p<0.05)is 1342,and the number of down-regulated genes in the HT(p<0.05)group is 1498.The cluster expression calorimetry of DEGs(Differentially expressed genes)between HT group and DIO group showed that the gene expression in HT group and DIO group was basically the same,and the expression difference between groups was more obvious.(4)GO enrichment analysis resultsAfter the GO database comparison,we got a total of 388 up-regulated GO terms,of which 241 were in the Biological Process(BP)part,100 were in the Cellular Component(CC)part,and 47 were in the Molecular Funtion(MF)Part;840down-regulated GO terms,including 709 in the BP part,50 in the CC part,and 81 in the MF part;the GO enrichment bubble chart shows that the 4 GO terms with the largest number of genes include mitochondrial protein complexes,ribosomes,ribosomal subunits,and structural components of ribosomes.The histogram of GO enrichment analysis shows that the DEGs between the HT group and the DIO group are the key genes for enzymatic catalytic function in the process of hypoxic training intervention in obese mice.(5)KEGG enrichment analysis resultsThe results of KEGG enrichment analysis bubble chart indicate that the metabolic pathways involved in DEGs are mainly related to the glucose and lipid metabolism process,the inflammation regulation process and the insulin signaling pathway.The chordal graph shows that in DEGs the genes closely related to glucose response are PIK3 CA,MUP1,INSR,HK2,DYNLL1 and ARRB1;genes closely related to the glucose metabolism process are PCK1,APOC3,HK2,SORBS1,NFE2L1 and C1QTNF1;and genes closely related to the ATP metabolism are HSRA8,CHCHD10,DYNLL1,APOC3 and TCF7L2;the genes closely related to the NF-k B signaling pathway are RPS6KA5,KRAS,TRIM14,CX3CR1,EDA2 R and NTRK1;There are some genes related closely to the Toll-like receptor signaling pathway,including CD14,ARF6,TLR2,TLR5,TLR7,and CD36.We observed 8up-regulated genes and 18 down-regulated genes in the NF-k B signaling pathway,and in the Toll-like receptor signaling pathway,we got 6 up-regulated genes and 18down-regulated genes.Conclusions(1)Hypoxic training significantly reduced the body weight of obese mice and improved the exercise ability of obese mice.It also significantly improved the lipid accumulation in the liver and other parts of obese mice,indicating that hypoxia training has the effect of optimizing body composition;(2)The effect of hypoxia training on glucose metabolism in obese mice may be regulated by the activation of PI3k/Akt signaling pathway and Fox O signaling pathway through insulin receptors;(3)Hypoxic training inhibits the inflammatory response of obese mice by down-regulating the expression of pro-inflammatory factors in the Toll-like receptor signaling pathway and NF-k B signaling pathway.