Normal And Deficiency State Of Rat Liver Dna Methylation Level Differences

"Essential study of Chinese herbal drug nature on base of three factors theory", which is supported by the Major State Basic Research Development Program of China (Program 973)(No.2007CB512605 ) focuses on investigating the factors of the formation and expression of Chinese herbal nature,it is supposed that drug nature is brief property derived fromits biological effects,which is related to chemical constitution and the state of organism.Therefore,the status of organism,chemical constitution and biological effects are considered to be three factors of drug nature.The organismplays a role in expression of biological effects of drugs.This study is searching for physiological indexes characterizing the status of organism and machanism of biological effects of drugs in different organism status.Our research have confirmed that the activity levels of liver metabolic enzyme are different in different organism statuses,and this study attempts to find out the possible reasons for the differences by researching DNA methylation,which refers to a process, whose catalyst is DNA methyltransferase(DNMTs),transferring the methyl to the 5 'position of the cytosine from S-adenosylmethionine(SAM).As a very common epigenetic event in mammalian genome,DNA methylation could restrict cells and tissues by impacting gene expression and regulating chromatin structure,and demonstrated the differences of physiological functions.In group to explore the molecular mechanism by which DNA methylation impacts organism status,this study observes the differences of the DNA methylation levels in different organism statuses by detecting the liver DNA methylation levels between the deficiency-cold type rats and normal rats.This study focuses on the following two parts.On one hand;establishing amethod of determination of DNA methylation in rat liver tissues by high performance liquid chromatography(HPLC),and extracting genomic DNA from rat liver tissues by phenol chloroform extracting method,and then hydrolyzing the DNA to single base by acid hydrolysis,in the end,determining the content of the base by HPLC. On the other hand,building the cold-deficiency type rat model by hydrocortisone agent,and then studying the differences of DNA methylation in liver tissues between the cold-deficiency type rats and normal rats,the results indicate that the.DNA methylation level of the liver tissues of the yang deficiency-cold type rats is much lower(P＜0.01) than that of normal rats,with a significant difference.From the analysis of the differences of DNA methylation in liver tissues between the deficiency-cold type rats and normal rats,we surmise that hydrocortisone,combined with the glucocorticoid receptors in cytoplasm,is transferred to the nucleolus,and then regulate the transcription to impact DNA methylation,whose differences impact the expression of the genetic information,finally,we can see the differences of physiological functions and statuses of the organism through the functional activities of protein molecules.The inferences above are yet to be proved by further experiments.