ABSTRACT
AIM:To study the effect of Hand2 (one of basic helix-loop-helix proteins’ transcription factors) expression on the development of the cardiac tissues in the fetal rats from gestational diabetes mellitus ( GDM) parents, and to investigate the potential pathogenesis of GDM-induced congenital cardiac defects in rats.METHODS: The adult Spra-gue-Dawley female rats were randomly divided into blank control group (n=24), GDM group (n=30), negative control group ( n=30) and insulin intervened group ( n=30) .The GDM model was established by intraperitoneal injection of 2%streptozotocin (STZ, 40 mg/kg body weight) to the pregnant rats on the successive day.The rats in insulin intervened group were injected with intermediate-acting insulin in order to keep the fasting blood glucose in the normal range.The rats in negative control group were injected with citric acid-sodium citrate buffer solution in the same position.Blood glucose and body weight were examined every day 72 h after STZ injection.On E12, E15 and E19, the rats were anesthetized and the embryonic cardiac tissues were collected after caesarean section.The histopathological changes of the cardiac tissues were observed under microscope with HE staining.The expression of Hand2 was analyzed by the method of immunohisto-chemistry.The expression of Hand2 in the cardiac tissues at mRNA and protein levels was determined by real-time fluores-cence quantitative PCR and Western blotting.RESULTS:During the development of embryonic heart, the protein expres-sion of Hand2 in the cardiac tissues was showed dynamic changes.Observed on E12, obviously increased on E15, and at the highest level on E19.Compared with the other 3 groups, the protein and mRNA expression of Hand2 in GDM group was decreased at the time points of E12 and E15.CONCLUSION:The morbidity of fetal cardiac malformation is significantly increased in GDM group, suggesting that Hand2 may be involved in the development of cardiac malformation in GDM.