| OBJECTIVE: To investigate the expression of cardiac specific transcriptional factorNkx2.5in fetal heart during pregnancy in maternal rats with gestational diabetes byestablishing rat models of diabetic pregnancy, and discuss the possible role of Nkx2.5inthe abnormal development of fetal heart induced by diabetic pregnancy.METHODS: The eighty pregnant female adult rats were randomly divided into experimentalgroup (n=40) and control group (n=40). The pregnant rats in the experimental group wereintraperitoneally injected with streptozocin (STZ) to induce diabetic pregnancy, whilethe pregnant rats in the control group were intraperitoneally injected with the same volume ofcitric acid/sodium citrate buffer. The blood sampling was collected from the caudal vein72hafter drug administration, and the blood glucose was examined daily. The pathology of fetalheart tissues with HE staining was observed, and the expressions of Nkx2.5protein in thefetal heart tissues were detected on day12,15and19of pregnancy.RESULTS:1.After drug administration for three days, the blood glucose levelof pregnant rats in the experimental group （15.00±0.76mmol/l vs4.00±0.62mmol/l，P <0.01）was significantly increased and this increasing trend continued until in the latepregnancy with typical clinical presentations of diabetes. The difference in the blood glucoselevel at the same time-point between the two groups was significant (P <0.01). The weightsof pregnant rats in the two groups were increased with the gestational age, and the weight ofthe pregnant rats in the experimental group was lower than that in the control group (P <0.01) since gestation of9days. The number of abortions in the experimental group wasincreased as compared with that in the control group on day12of pregnancy (P <0.05).Compared with the fetal rats in the control group, the weight was decreased and the numbersof giant fetus(P <0.01), abnormal heart and abnormal fetus were all increased in the fetalrats in the experimental group (P <0.01).2.The result of immunohistochemistry showed that the expression of Nkx2.5protein in cardiac myocytes in the control group was slightly increased by the gestational age, and theNkx2.5protein expression in the experimental group had a great increase during12-15daysof gestation and it was significantly decreased as compared with that in the control group atthe same gestational age (P <0.01).CONCLUSION: The abnormal cardiac development was more frequent in the fetal ratsdelivered by maternal rats with gestational diabetes, and there was a decline trend in theexpression of Nkx2.5protein which was significantly decreased in the fetal myocardialtissues on day12,15and19of pregnancy. These results suggest that the Nkx2.5may beinvolved in the pathogenesis of congenital heart diseases induced by gestational diabetes. |
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