Teratogenic Effect of X-ray on Cardiovascular System of Chick Embryo

BACKGROUND AND OBJECTIVES: Laboratory research was carried out to investigate the teratogenic effect of X-ray on chick embryos, especially with regard to cardiovascular malformation. MATERIALS AND METHODS: The chick embryos, 242, 242 and 215 eggs, were irradiated with X-ray at the dose of 500, 750 and 1000 cGy, respectively, during the incubation period between 0 and 9 days. A control group of 90 eggs received no irradiation. After 2 weeks of incubation, the embryos were sacrificed and examined. RESULTS: The survival rate of irradiated group was significantly lower than that of control group (62.5 vs. 87.8%, p<0.0001). The incidence rate of cardiovascular malformation was significantly higher in the irradiated than the control group (16.2 vs. 2.5%, p<0.005). The rate of cardiovascular malformation in the irradiated group increased from 9.4% with 500 cGy to 24.5% with 1000 cGy (p<0.05). There were a total of 33 cases of cardiac malformation, of which 24 were ventricular septal defects and 9 were complex congenital heart diseases. The higher the administered dose of radiation, the higher the observed incidence rate of cardiac malformation and the more complex the cardiac anomaly. Also, the rates of exocardia, exencephaly, beak anomalies and anopia were all increased in the irradiated group. CONCLUSION: X-ray irradiation of chick embryos increased the rates of death and cardiovascular malformation. The highest dose resulted in greater complexity of the cardiovascular malformation.

Experimental Study for the Teratogenic Effect of Gamma-ray on the Heart of Chick Embryo

PURPOSE: To investigate the teratogenic effect of gamma-ray on the heart of chick embryo. METHODS: 50 rad, 100 rad, 150 rad, 200 rad, 250 rad, and 300 rad of gamma-ray were used to irradiate three days old chick embryos. The control group was not irradiated. After three weeks, the embryos were sacrificed and examined for cardiovascular malformation. RESULTS: The survival rate of the gamma-ray irradiated group was significantly lower than that of the control group(33.3-63.3% vs 76.4%, P=0.001). The cardiac malformation rate of the experimental group was 11.0%. In the control group, no congenital cardiac malformations were observed. The experimental groups had a significantly higher malformation rate(P=0.001). The types of malformation were ventricular septal defect, tricuspid atresia, Ebstein anomaly and aortic arch anomaly. In the gamma-ray irradiated group, the cardiac malformations were : 14 small ventricular septal defects (VSDs), five large VSDs, two tricuspid atresias, and one Ebstein anomaly. The higher the dose of radiation applied, the higher the incidence of cardiac malformation was noted. CONCLUSION: Gamma-ray irradiation of 3 days old chick embryos increased the rate of death and the rate of cardiac malformation significantly.

Teratogenic Effect of Dopamine on the Embryonic Chick Heart

PURPOSE: To investigate the teratogenic potential of dopamine using a topical method of application to the developing Korean native chick embryo. METHODS: A 5 pg(0.05cc) of dopamine was applied to a 3-days-old chick embryo and the same amount of saline solution was applied as control. The embryo was then returned to the incubator and monitored. After 3 weeks the embryo was sacrificed and examined for cardiovascular malformation. RESULTS: The survival rate of the dopamine-administered group was not significantly lower than that of the control group(32.2% vs 41.5%). Cardiovascular malformation rates between the two groups were 14.3% and 2.6%, respectively. The dopamine-administered group had significant higher malformation rate(P=0.049). The type of malformation was ventricular septal defect and no aortic arch anomaly. In the control group, one trabecular type was observed. In the dopamineadministered group, malformations were 3 trabecular ventricular septal defects(VSDs), 2 infracrista VSDs, 1 inlet VSD and 1 large supracrista VSD. These results were quite different from each other. CONCLUSION: We proposed that low doses of dopamine influence the cardiovascular morphogenesis through -1 receptor weakly or through dopaminergic receptor.