The Effect Of Zinc Deficiency During Pregnancy On Key Transcription Factors Of Embryonic Rats Heat Development

2.1 Objective This study aim to investigate cardiac malformation and change of key transcription factors of embryonic rats heat development process through establishing zinc deficient model of pregnant rats.2.2 Methods 27 SD-healthy rats of clean grade were randomly divided into 3 groups,nine in each group: paired feed group(feed zinc content 30ug/g),zinc deficient group(feed zinc content 5ug/g),normal zinc group(30ug/g).Pregnant rats in each group were fed respectively with different zinc content feed,paired feed group were provided normal feed,but the quantity equaled the intake of zinc deficiency group rats intake the day before.All the pregnant rats were killed on the 19 th day during pregnancy,and achieved their venous blood whose zinc level can be determined through atomic absorption spectro photometer.Meanwhile fetal rat hearts can be used for observation of morph ological features and histologic examination.The expression of GATA4,Islet-1,NKx2-5 protein and m RNA in the heart tissue of fetal rats respectively were assayed by Western-blotting and Real time PCR.The concentrations of SOD,IL-1? in the plasma were measured by Elisa.2.3 Results 2.3.1 Under light microscopy,The abnormal changes of myocardial cells,nucleus,and chromatin structure were morphologically appeared in zinc deficient group.There is no obvious abnormal structural changes in the fetal rats heart tissue of paired feed group and normal zinc group.2.3.2 Zinc deficiency had impact on lowering the levels of Islet-1,GATA4 protein and GATA4,Nkx2-5,Islet-1m RNA in the heart tissue of fetal rats,but that was not on the level of Nkx2-5protein.As compared with the normalzinc group,Islet-1,GATA4 protein and GATA4,Nkx2-5,Islet-1m RNA were significantly lower in the zinc deficient group,there were statistically signif icant difference(P<0.05).There was no statistically significant difference between paired fee-d group and normal zinc group about the level of three kinds of protein and t-heir mRNA(P>0.05).2.3.3 Zinc deficiency had impact on lowering the levels of SOD in fetal rats serum(P<0.05)and increasing the levels of IL-1?(P<0.05).The difference was statistically significant,the difference between paired feed group and normal zinc group is not significant(P>0.05).2.4 Conclusions 2.4.1 Under light microscopy,The abnormal changes of myocardial cells,nucleus,and chromatin structure were morphologically appeared in zinc deficient group.There is no obvious abnormal structural changes in the fetal rats heart tissue of paired feed group and normal zinc group.That prompt zinc de ficiency can lead to cardiovascular malformations on fetal heart development.2.4.2 Zinc deficiency had impact on lowering the levels of Islet-1,GATA4 pr otein and GATA4,Nkx2-5,Islet-1mRNA in the heart tissue of fetal rats,which suggests zinc deficiency has certain influence on fetal rats heart develop ment and its mechanism may be related to inhibit the expressions of GATA4,Nkx2-5,Islet-1 mRNA and decrease the related protein of heart development,eventually leading to changes in the structural abnormalities of fetal rat hearts.2.4.3 Zinc deficiency had impact on lowering the levels of SOD in fetal rats serum(P<0.05)and increasing the levels of IL-1?(P<0.05).Zinc deficie ncy induces Oxidative stress and inflammatory response which may be an another mechanism of its effect on congenital cardiac abnormalities in fetal rats.