| Subterranean rodents is a kind of rodent mammals which live undergound for lifetime and have always adapted to hypoxia and carbon dioxide enviroment.It is reported that the resting metabolic rate of the subterranean rodents is low,the purpose is to save energy for more digging and foraging activities.Energy is essential for the survival and development of organisms,its production occurs in the process of material metabolism,in which sugar metabolism for the body life activities to provide the vast majority of energy.In addition,the liver is the main metabolic organ of mammalian mammals,plays an important role in maintaining energy balance.Therefore,the study of liver glucose metabolism in subterranean rodents can help to reveal the hypoxic adaptation mechanism of subterranean rodents.Eospalax cansus is a typical subterranean rodent,so it could be the ideal material to study the evolution of subterranean rodents.Transcriptome sequencing technology is a new generation of sequencing technology,has the advantage of high accuracy,responsive and the large amount of data.People can get all the transcription of the information when a tissue or cell in a certain condition by it.We sequencing Eospalax cansus liver in the oxygen content of 21%,10.5%and 6.5%by Illumina HiSeq 2500 in this study.The results show a lot of genes and metabolic pathways associated with substance metabolism.In order to investigate the characteristics of glucose metabolism during the hypoxia adaptation process in Eospalax cansus,we choose the hepatocyte nuclear factor-4a(HNF-4a),hepatocyte nuclear factor-la(HNF-la)and glucokinase(GCK)as the research contents.The HNF-4a,HNF-la and GCK genes were quantified by real-time quantitative PCR,and SD rats were used as controls.Through analyzing the mRNA expression of HNF-4a,HNF-1? and GCK genes under different oxygen concentration conditions to discuss the characteristics of glucose metabolism in Eospalax cansus preliminarily,which aims to lay the foundation for the study of hypoxia adaptation mechanism in subterranean rodents.The main findings and conclusions are as follows:1.The mRNA expression of HFN-4a gene was significantly down-regulated in hypoxia(10.5%,6.5%oxygen concentration),and 6.5%oxygen concentration was significantly lower than that of 10.5%.Because of its long-term adaptation to hypoxic environment,the function of HNF-4a to inhibition Gluconeogenesis can develop normally.While 21%oxygen concentration was hyperoxia to Eospalax cansus,it stimulated the high expression of HFN-4a gene,so the gene to code PEPCK was downregulated,cause the rate of gluconeogenesis was slowed down to maintain the balance of glucose metabolism in hyperoxia condition of Eospalax cansus.The expression of HNF-4a in the SD rats was significantly lower than that in the control group,it cause the speed of inhibited the rate of gluconeogenesis slowed down and result in glycogen increased output,but the expression of HNF-4a was significantly increased in 6.5%oxygen concentration,it increased the efficiency of gluconeogenesis,so as to maintain the normal glucose metabolism under acute hypoxia.The expression of genes in SD rats was significantly higher than that in Eospalax cansus at each oxygen concentration,which indicated that SD rats were required to express this gene normally in order to maintain the function of glucose metabolism,while that of Eospalax cansus was conversely,it shows that Eospalax cansus has a strong ability to adapt to environmental changes.2.The expression of HNF-la gene was the highest at 10.5%oxygen concentration in Eospalax cansus,and it was significantly down-regulated at 21%and 6.5%oxygen concentration,because the glycolysis was not the main pathway of energy source under normal oxygen concentration.HNF-1? down-regulated when under the condition of acute hypoxia,so the inhibition of glycolytic function weakened and glucose decomposition rate to maintain blood glucose balance.The expression of HNF-la mRNA was significantly increased with the decrease of oxygen concentration,and the inhibition of glycolysis was stronger,and then the blood glucose increased significantly,which could cause SD rats to have glucose metabolism disorder,which may be SD rats were not adapt to hypoxia.The gene expression of HNF-la was significantly higher than that of SD rats at 21%and 10.5%oxygen concentration in Eospalax cansus and SD rats at various oxygen concentrations,which may be in order to save energy.And gene expression in SD rats was significantly higher than that of Eospalax cansus under 6.5%oxygen concentration,it could increase the rate of glycolysis in to maintain blood glucose balance.Therefore,the function of HNF-1? to maintain glucose metabolism in hypoxic conditions could be better to play in Eospalax cansus.3.The expression of GCK gene was the highest at 10.5%oxygen concentration in Eospalax cansus,and the 21%and 6.5%oxygen concentrations were significantly down-regulated.The glycolysis at normal oxygen concentration was not the main wav to obtain energy,the rate of metabolic process of glucose-6-phosphate is reduced under acute hypoxia,it cause the rate of glycolysis is reduced,then the increase of glucose concentration may lead to disorder of glucose metabolism.SD rats had no significant difference in the expression of GCK gene at 21%and 10.5%oxygen concentration,it was hypothesized that SD rats could only express this gene extremely to maintain the glycolysis rate in the chronic hypoxic condition,o but at the 6.5%oxygen concentration was significantly reduced,this may lead to SD rats glucose metabolism disorders.Due to the extent of gene down-regulation in SD rats was higher than Eospalax cansus under the condition of 6.5%oxygen concentration,so the regulation of glucose metabolism in GCK of Eospalax cansus can be better.In additon,the expression of genes in SD rats was significantly higher than that in Eospalax cansus at each oxygen concentration,it showed that the high expression of GCK was beneficial to ensure the normal glucose metabolism.4.In the metabolic pathway of HNF-4a,HNF-la and GCK,the expression level of MafA in Eospalax cansus was significantly increased under the condition of 6.5%oxygen concentration,but PDX1 and NeuroD1were not expressed,which come into play with MafA.In the case of insulin gene expression is not expressed,but Eospalax cansus can still maintain normal glucose metabolism,it is speculated that there have compensatory mechanism in glucose metabolism.5.Through PCR to amplify cDNA fragment of HNF-4a,GCK and HNF-lathat were annotated in NR database,then blast the sequencing in the NCBI,the results showed that the homology with blind mole rat could be above 90%,so it's certain that gene c91655.graph_c0,c92171.graph_c0 and c88937.graph_c0 are HNF-4?,GCK and HNF-1?in Eospalax cansus liver. |
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