2020 Volume 36 Issue 2 Pages 121-127
Bis-diamine is a potent teratogen in rats which induces conotruncal diseases and thymic hypoplasia similar to those seen in chromosome 22q11 deletion syndrome in humans. The precise mechanism of the cardiac teratogenic effects of bis-diamine is unknown. Bis-diamine was administered to 40 pregnant rats on the 10th day of gestation at a dose of 200 mg. Following cervical dislocation of these rats on the 21st day of gestation, the fetuses were delivered by Cesarean section and were then frozen immediately in acetone cooled to −76°C with dry ice. Each frozen fetus thorax was cut transversely and the section surface was serially photographed with a stereoscopic microscope (Wild M400 Photomacroscope) every 500 microns. The following cardiac diseases were recorded in 330 fetuses: tetralogy of Fallot (16％), tetralogy of Fallot with absent pulmonary valve (14％), tetralogy of Fallot with pulmonary valvular and infundibular atresia (38％), truncus arteriosus (10％), ventricular septal defect (3％), interrupted aortic arch type B (2％), and atrioventricular septal defect (2％). These diseases are animal models of fetal echocardiographic diagnoses representing congenital heart diseases associated with chromosome 22q11.2 deletion syndrome, and the cross-sectional morphologies represent a graphical review of these condition. These are additional graphs of hypoplastic or absent thymus, interrupted aortic arch, and vascular ring.
