The Regulatpry Mechanism Of CYP3A1 And UGT1A1 In Hypobaric Hypoxia

The features of high altitude are hypopiesia,hypoxia,strong ultraviolet rays,cold and dry environment,hypoxia is the important factor influenced organism among these features.But there is no difference in the method and dosage of taking medicine between high altitude and plain,the safety and efficiency of plateau people wil be effected when they take medicine to cure desease.It is well known the drug-metabolizing enzyme is the major tool that take part in the process of drugs' biotransformation,catalysis and detoxification.Currently,the regulatory mechanism of enzymes in hypoxia is unclear,so it is necessary to investigage the influence of hypoxia to enzyme.This project chose CYP3A1 and UGT1A1 as the symbol,and research the change of CYP3A1 and UGT1A1 after acute exposure to high altitude.because nuclear receptor and cytokines are regulatory factors of enzyme,then we combined the change of nuclear receptor and cytokines to discuss the regulatory mechanism.Healthy adult Wistar rats were randomly divided into Control group(normal feeding in Lanzhou,Gansu),High altitude group(hypoxia 12 h,24h,36 h,48h).the high altitude group was managed by acute exposure to Yushu,Qinghai.This project was divided into four parts as follows: Part one,to study the effect of hypoxia on high altitude,we investigated the indicator of blood gas and biochemical,and then observed the pathologic change of liver;Part two,we explored the change of drug metabolism enzyme CYP3A1 and UGT1A1 in plateau,the Realtime PCR and Western blot were utilized to detect the gene and protein expression of CYP3A1 and UGT1A1.Part three,to estimate the changes of regulatory factors after exposure to high altitude,we used Real-time PCR and Western blot to detect the expression of PXR and CAR and used protein chip to study the changes of cytokines,and then analysed the correlation of regulatory factors(PXR,CAR and various cytokines)and drug metabolism enzyme(CYP3A1 and UGT1A1);Part four,because of the complexity of organism,we proved the correlation and mechanism of cytokine and enzymes in vitro;The results of Part one showed available O2,p H and total protein decreased,the ALT and AST increased when the rats were exposed in high altitude,this results remind us that the liver maybe had physiologic changes.Besides,we utilized pathological section find that the morphology and function of liver were negative effected.The pathological result shown that the liver's cell was slightly damaged,blood vessel appeared congestion and central veins appeared edema and inflammatory infiltration,these appearances showed us the liver's function may be damaged.Liver is the key organ of the metabolism,whose dysfunction would influence the synthesis and expression of drug-metabolizing enzyme so as to interfere the metabolic process.The results of Part two demonstrated the expression of CYP3A1 and UGT1A1 have significantly decreased after acute exposure to high altitude,we can learn that metabolism of some drugs would be slower than normal situation,and the clear rate maybe decrease so as to the increase of residence time would induce toxity of drug.The results of Part three have shown that the m RNA expression of PXR and CAR was decreased after 12 h of acute exposure to high altitude,and so as to we can guess the PXR and CAR regulated the transcription of CYP3A1 and UGT1A1 as the upstream gene according to references;then we can learn that the contents of IFN-?,IL-4 and IL-6 were increased after 48 h of acute exposure to high altitude and the contents of IL-10,IL-13 and MCP-1 were increased after 24 h.Finally,we formed the conclusion by analysis of correlation that IFN-? and IL-6 have strongly negative correlation with CYP3A1,IL-6 have strongly negative correlation with UGT1A1,and eventually we verified the correlation in Part four and comfirmed the regulation of IFN-? and IL-6.Finally,the results of Part four indicated that IFN-? would decrease the expression of CYP3A1 and UGT1A1 m RNA after 12 h of incubation and the expression would gradually increase as the extension of incubated time.Similarly,IL-6 would decrease the expression of CYP3A1 m RNA after 12 h and 24 h of incubation and the expression of UGT1A1 m RNA after 12 h of incubation.As the extension of time,the expression of CYP3A1 and UGT1A1 m RNA have increased and tended to normal.The whole project showed that IFN-? and IL-6 play a role in the regulation of CYP3A1 and UGT1A1 transcription,and this process is related to time of incubation,we guess that the feedback system would regulate the expression of enzyme to normal as the extension of incubated time.Our project aimed to investigate the regulatory mechanism of CYP3A1 and UGT1A1 in the high altitude,we can make a major conclusion as followes: the liver's inflammation reduced the expression of CYP3A1 and UGT1A1 when the rats were exposed in high altitude.Besides,the Nuclear receptor PXR and CAR maybe regulate CYP3A1 and UGT1A1.