ABSTRACT
ObjectiveTo explore the effect of selenium,protein and vitamin E deficiency on mRNA expression of rat cardiac selenoprotein,and their relation with myocardial injury.MethodsForty male Wistar rats were randomly divided into 4 groups:low selenium low protein low vitamin E group(group A),low selenium low protein adequate vitamin E group(group B),adequate selenium adequate protein low vitamin E group(group C),and adequate selenium adequate protein adequate vitamin E group (group D),10 rats in each group.The activity of whole blood glùtathione peroxidase(GSH-Px ) was measured using dithiobis nitrobenzoic acid (DTNB) at the end of sixth month experiment.The levels of mRNA expression of glutathione peroxidase 1(Gpx1),phospholipid hydroperoxide glutathione peroxidase 4(Gpx4),thioredoxin reductase(TrxR),selenoprotein P(Se-P) and selenoprotein W(Se-W) were determined by real-time fluorescence quantitative PCR at the end of sixth month.Histopathological changes of myocardial injury were observed with light microscope.ResultsThe activity of GSH-Px was (44.6 ± 3.1 ),(45.5 ± 1.6),(86.6 ± 2.2),(85.6 ± 1.2)U/L,respectively,in the above four groups at the end of sixth month,and the difference was statistically significant(F =100.7,P ＜ 0.01 ) ; the activity of GSH-Px of groups C and D was higher than that of groups A,B(all P ＜ 0.05).mRNA expression of myocardial tissue of the four groups was as follows,Gpx1(0.099 ± 0.312,0.054 ± 0.007,0.386 ± 0.067,0.340 ± 0.085),Gpx4(1.005 ± 0.089,0.810 ± 0.229,0.895 ± 0.084,0.922 ± 0.399),and Se-W(0.188 ± 0.080,0.119 ± 0.069,0.574 ± 0.167,0.570 ± 0.383),and the difference was statistically significant(F =112.1,3.76,22.8,all P ＜ 0.05) ; the mRNA levels of Gpx1,Se-W of groups C,D were significantly higher than that of groups A,B(all P ＜ 0.05).The mRNA expression of Gpx4 of group A was higher than that of group C(P ＜ 0.05).The mRNA expression of TrxR(0.130 ± 0.037,0.127 ± 0.038,0.134 ± 0.021,0.120 ± 0.014) and Se-P(0.446 ± 0.155,0.413 ± 0.152,0.385 ± 0.041,0.408 ±0.208 ) was not statistically different among the four groups (F =0.91,1.75,all P ＞ 0.05).Pathological changes of myocardial tissue were mainly as foci of coagulative necrosis.The necrosis detection rate of the four groups was 8/10,4/9,2/10,and 1/10,respectively,and the difference was significant statistically(Fisher exact test,P =0.0067).ConclusionsLong-term selenium,protein and vitamin E deficiency will reduce body antioxidant capacity and lead to myocardial injury.The mRNA levels of Gpx1 and Se-W and selenium level are closely related.The mRNA levels of Gpx4,TrxR and Se-P remain relatively stable.
ABSTRACT
Objective To observe protective effects on rat serum cardiac enzymes and the antioxidant capacity of selenium and vitamin E.Methods According to body weight and 2 × 2 factorial design,eighty male Wistas rats were randomly divided into four groups:low selenium and low vitamin E group(feed containing 23.42％ of the low selenium yeast,excluding vitamin E),low selenium and adequate vitamin E group (feed containing 23.42％ of the low selenium yeast and vitamin E 160 mg/kg),adequate selenium and low vitamin E group(feed containing 46.84％ of the low selenium yeast and sodium seleni 0.25 mg/L in water,excluding vitamin E),adequate selenium and adequate vitamin E group(feed containing 46.84％ of the low selenium yeast,vitamin E 160 mg/kg and sodium selenite 0.25 mg/L in water),20 rats every group.Rats were feed with synthetic feed,and given intraperitoneal anesthesia after 26 weeks of feeding.Blood was collected to observe the impact of selenium and vitamin E on rat cardiac enzymes and myocardial antioxidant capacity and their interactions.Serum creatine kinase (CK) was measured using the continuous monitoring method,creatine kinase isozymes (CK-MB) and lactate dehydrogenase(LDH ) using the immune suppression method,the whole blood GSH-Px assay using the dithiobis nitrohenzoic acid(DTNB) method,serum superoxide dismutase(SOD) using the xanthine oxidase method,total antioxidant capacity (T-AOC) using the complex colorimetry method,the content of propylene glycol (MDA) using the thiobarbituric acid colorimetric method,and reactive oxygen species(ROS) using the colorimetric method.Results Group differences of serum CK,CK-MB,LDH,whole blood GSH-Px activity,serum T-AOC vitality,MDA and ROS content were statistically significant(F=9.797,17.041,48.399,3.744,224.900,49.384,5.045,all P＜ 0.05).Compared with the two low selenium groups and one adequate selenium group,the vitalities of CK,CK-MB,LDH and the contents of MDA[(1577.75 ± 451.87),(1239.15 ± 344.99),(884.25 ± 133.84)U/L,(5.688 ±1.169) × 103 nmol/L; (1474.21 ± 398.38),(1014.84 ± 215.40),(523.00 ± 98.05)U/L,(4.035 ± 0.487 ) × 103 nmol/L and (1180.10 ± 245.51),(948.75 ± 173.68),(676.70 ± 193.63)U/L,(3.406 ± 0.146) × 103 nmol/L]increased significantly in adequate selenium and adequate vitamin E group[( 1056.80 ± 250.98),(721.70 ±129.98),(404.65 ± 72.49)U/L,(3.010 ± 1.270) × 103 nmol/L,all P ＜ 0.05) ].The activity of GSH-Px was obviously increased in the two adequate selenium groups[ (96.611 ± 8.238) × 103,(103.024 ± 8.217) × 103 U/L,all P ＜ 0.05],compared with the two low selenium groups[ (60.356 ± 8.179) × 103,(63.117 ± 8.281) × 103 U/L].Selenium affected the activities of CK,CK-MB and LDH(F =27.09,31.58,29.66,all P＜ 0.01 ),and vitamin E affected the activities of CK-MB and LDH(F=18.9,11.2.all P＜ 0.01 ),but both selenium and vitamin E had no interactions on the activities of CK,CK-MB and LDH (F=0.02,0.001,2.22,all P＞0.05).Selenium affected the activity of GSH-Px and the content of MDA(F=6.74,95.68,all P＜ 0.05),vitamin E affected the activity of T-AOC,the contents of MDA and ROS(F=6.42,36.73,8.43,all P＜0.05),but selenium and vitamin E had interactions only on the content of MDA(F =13.82,P＜ 0.05).Conclusions Long-term selenium or vitamin E deficiency,can reduce the body's antioxidant capacity,leading to the occurrence of myocardial injury.Selenium and vitamin E can improve the body's oxidation capacity,playing a role in myocardial protection.