Effects Of X-ray Irradiation On The Activity,Protein And MRNA Expression Of CYP1A2 And CYP2E1

Objective:To study the effects of X-ray on the activities,protein and mRNA expression of drug-metabolizing enzymes CYP1A2,CYP2E1 by combining radiation with drug metabolism.Methods:SD rats were randomly divided into two groups:CYP1A2 group and CYP2E1 group.Each group was randomly divided into three groups:control group,low-dose radiation group（1Gy）and high-dose radiation group（5Gy）.The rats were irradiated by 6MV X-Rays with whole body irradiation by the Va Rian 23EX medical electronic linear accelerator.Caffeine and chlorzoxazone,the probes of CYP1A2 and CYP2E1,were selected by Cocktail method after establishing the model and the activity of CYP1A2 and CYP2E1 were evaluated by pharmacokinetic changes of probes.Blood samples were collected at 0.083,0.167,0.333,0.5,1,2,4,6,8,12 h from fundus veins of rats in CYP1A2 and CYP2E1 groups after single-dose intragastric administration of probes to determine the concentration of caffeine and chlorzoxazone in plasma by HPLC.The pharmacokinetic parameters of probes in the control,low and high-dose radiation groups were calculated by non-atrioventricular model with DAS 2.0 pharmacokinetic software to evaluate the effect of X-ray on the activity of CYP1A2 and CYP2E1.The changes of thymus,spleen index and physiological indexes such as hemoglobin（HGB）,white blood cell（WBC）,red blood cell（RBC）,total protein（TP）,platelet count（PLT）,alkaline phosphatase（ALP）,creatinine（CRE）and uric acid（UA）were determined and calculated;Enzyme linked immunosorbent assay（ELISA）and Real-time Quantitative PCR（qPCR）were used to determine the protein and mRNA expression on CYP1A2 and CYP2E1 of liver and to evaluate the effect of X-ray on the protein and mRNA expression of these two enzyme.Results:Compared with the control group,the index of thymus and spleen of rats in the low and high-dose radiation groups were significantly decreased by 41.8%,72.8%（P<0.05）and by 19.9%,56.8%（P<0.05）.Blood routine showed there was no significant change in RBC and HGB but a decrease of WBC by 26%and 61%（P<0.05）and a increase of PLT by 149%and 87%in the low and high-dose radiation group（P<0.05）,than that of control group.ALP was decreased by 39.6%in the high-dose radiation group but no significantly change in the low-dose radiation group,TP was increased by 15.3%,14.1%（P<0.05）and GLO was increased by 26.7%,20.7%（P<0.05）in the low and high-dose radiation groups.The activity of CYP1A2 in rats was increased significantly and the pharmacokinetic parameters of caffeine changed obliviously after X-ray irradiation.The results showed that the t1/2 were significantly reduced by 24.7%and 41.1%（P<0.05）;MRT_0-t was reduced by 10.7%and 33.1%（P<0.05）;AUMC_0-t was significantly decreased by 40.4%and 60.2%（P<0.05）;Cmax was significantly reduced by 32.7%and 48.1%（P<0.05）in the low and high-dose radiation group.The activity of CYP2E1 in rats was increased significantly after X-ray irradiation,as well.The results showed that CL was increased by 44.1%and 90.5%（P<0.05）;AUC_0-t were significantly reduced by 29.7%and 90.5%（P<0.05）;AUC_0-∞was significantly reduced by 28.4%and 43.2%（P<0.05）;Cmax was decreased by 32.7%and 48.1%（P<0.05）in the low and high-dose radiation group compared with the control group.X-ray irradiation significantly increased the protein expression of CYP1A2 and CYP2E1 in rats.Compared with the control group,the protein expression of CYP1A2was significantly increased by 28.3%,38.9%（P<0.05）in the low and high-dose radiation groups.Meanwhile,the protein expression of CYP2E1 was significantly increased by 48.4%（P<0.05）in the high-dose radiation group,but there was no obviously change of the protein expression of CYP2E1 in the low-dose radiation group though there was an increasing trend.Compared with the control group,the mRNA expression of CYP1A2 was significantly increased by 856%（P<0.05）in the high-dose radiation group and there was no prominent change in the low-dose radiation group.At the same time,the mRNA expression of CYP2E1 was increased significantly by 89%and 192%（P<0.05）in the low and high dose radiation groups.Conclusion:X-Ray has certain effects on various physiological indexes of rats which causes damage to liver and kidney of rats.X-Rays significantly increased the activity,protein and mRNA expression of CYP1A2 and CYP2E1.