Effects Of Selenium On Expression Of GPX1 And GPX4 In Myocardium Of Rats And Case - Control Study On GPX1 Gene Polymorphism In Keshan Disease Patients

Objective To study the affect of Selenium and protein on ratmyocardial GPX1,GPX4expression and translation.,and molecular epidemiology of Genepolymorphism of GPX1of keshan disease patients.Methods1．60healthy male Wistar rats were randomly divided into fourgroups,each group has15rats.(A) Low-protein and low selenium group;(B)low-protein and normal selenium group;(C) low-selenium and normal group;(D)mormal seleniumand normal protein group.Kill the rats after12months’ feeding,measure the activity of GSH-Px, the c level of liver of each group and Cardiac index;Observing the Pathological changes of myocardial cells by Optical microscope andcalculating the rate of Myocardial necrosis; Examing the expression of proein level ofGPX1、GPX4and SBP2by Western blot;Extracting Total RNA of cardiac tissue,Amplifying the sequences of SECIS of GPX1, GPX4mRNA by RT-PCR,examing thebase sequent after screening the genotypes by SSCP.2．Examing the patientsaccording to GB17021-1997in KeShan disease area and screening the subjects byexaming the content of selenium of blood by hydride generator atomic fluorescencespectrometry,the activity of GSH-PX of blood by Dithionitrobenzoic acid and thegene polymorphism of by DNFP.Results Animal experiments show that the activity of GSH-Px of low-selenium is lower than the normal group obviously, the difference issignificant(P<0.001);The selenium of liver of normal group is higher than the low-selenium group（P<0.001）;The rats’Cardiac index of the Low-protein and lowselenium group is higher than other groups, the difference is significant(P<0.001); Wefound out that different degrees of myocardial necrosis occurred in all groups, thenature of disease is spotty coagulative necrosis, With a few of inflammatory cells infiltration.The highest rate of myocardial necrosis is group A(71.4%),the next isgroup C(40%),group B(21.4%) and group D (6.7%).The differences between the fourgroups are significant;Low-selenium and low-protein have effects on reducing thecontent of GPX1of cardiac tissue(P<0.01) and low selenium and low-protein haveinteractions with each other;The content of GPx4of myocardial tissue of low-selenium group is lower than the normal-selenium group(P<0.05); Low-selenium andlow-protein have effects on reducing the content of SBP2of cardiactissue(P<0.01),hower,there is no interaction between selenium and protein. TheSECIS base sequence on the mRNA of GPX1and GPX4has not mutated. The basesequences do not vary on mRNA of GPX1、GPX4.The case control study shows thatthis study include72persons,the case group have38persons and the control grouphave34persons.The selenium level of blood and the activity of GSH-PX of casegroup is lower than control group.There are25Gene mutation spots.Thereinto, themutate rate of475th expressed region is higher the control group.Conclusions1.low-selenium and low-protein could lead to Myocardial injury and highCardiac index,the injury is mainly spotty coagulative necrosis, With a few ofinflammatory cells infiltration.2.The activity of blood GSH-Px rely on the intake of exogenous Addingselenium can significantly improve activity of GSH-Px.3.On condition of low-selenium and low-protein,the content of myocardialantioxidant enzymes GPX1and GPX4reduce significantly, producing Excessiveoxygen free radicals,then inducing myocardial damage and necrosis. IncreasingOxidative stress in the body.4.The content of SBP2of Cardiac tissue Promote the expression of cardiacselenium-protein, however,the SECIS base sequence on the mRNA of GPX1andGPX4has not mutated. 5.The difference among selenium level of keshan disease patient is notsignificantly.6.The field epidemiological investigation show that there is no significantdifference between case group and control group（t=1.475,P﹥0.05）except the475thspot;T test show that activity of GSH-PX in general have differences in general（t=3.131,P<0.05）,the activity of case group is lower than control group;There are25Mutated spot in case group ang control group in total,thereinto, the475thexpressed region significant(X2=4.11,P﹤0.1).The relationship between the reductionof the activity of GSH-PX and the genetic polymorphism is gonging to be Confirmedby further studies.