Mechanism of coronary artery anomalies and myocardial growth disturbance in bis-diamine treated rat using whole embryo culture technique

1.取孕10.5天的Wistar大鼠胚胎，进行全胚胎培养，连续观察心包发育情况。从横隔开始培养12小时后，首次发现发育中的心包，并开始覆盖胚胎心脏。结果：1.培养36小时后，心包完全被心包覆盖，随着发育的进行，心包逐渐接近心脏表面。于孕10.5天给孕鼠注射双二胺，给药后3h处死母鼠进行全胚胎培养。培养胚胎经双二胺处理后，心包发育延迟，培养36h后，整个心脏仍未被心包覆盖。在一些培养胚胎中发现了心包的缺陷。心包发育较晚，但不靠近心表。双二胺于孕10.5天给母鼠灌胃，14.5~17.5天摘除胚胎。大鼠于处死前1h腹腔注射BrdU。未经双二胺处理的对照胚胎在妊娠15.5d时，心肌对BrdU的摄取增加。双二胺处理的胚胎，室壁较薄，对BrdU的摄取减少，提示双二胺延缓了心包的发育，阻止了心包与心室表面的接触，从而延缓了冠脉循环的建立。用双双胺处理的胚胎中观察到的室壁变薄可能是由于流向发育中的心肌的血液不足所致。

1. The embryos were removed from pregnant Wistar rats on 10.5 day of gestation and whole embryo culture was performed to observe the development of the pericardium serially. The developing pericardium was first noted 12 hours after beginning of culture from the transverse septum and started to cover over the embryonic heart. At 36 hours after beginning of culture, the heart was completely covered with the pericardium and, subsequently, the pericardium was approaching to the surface of the heart as the development was advanced.2. Bis-diamine was administered to the pregnant rats on 10.5 day of gestation and the mother rats were sacrificed three hours after administration for whole embryo culture. The development of the pericardium was delayed in the cultured embryo treated with bis-diamine and the whole heart was not covered with the pericardium even 36 hours after beginning of culture. The defects of the pericardium were found in some cultured embryos. The pericardium developed later, but was not close to the surface of the heart.3. Bis-diamine was given to the mother rats on 10.5 day of gestation and the embryos were removed from 14.5 to 17.5 day of gestation. BrdU was administered to the rats intraperitoneally one hour before the rats were sacrificed. The control embryos without treatment of bis-diamine showed that the uptake of BrdU to the ventricular wall muscle was increased on 15.5 day of gestation. In the embryos treated with bis-diamine, the ventricular wall was quite thin and the uptake of BrdU was diminished.These results suggested that bis-diamine delayed the development of the pericardium and prevent from the contact of the pericardium to the ventricular surface and, subsequently, the establishment of the coronary circulation was retarded. The thin ventricular wall observed in the embryos treated with bis-dimaine may be caused by the insufficient blood flow to the developing myocardium.