Human Embryonic Germ Cells Transplantation To Cure The Acute Myocardial Infarction In Swine And The Myocardial Regeneration

Objectives:1. To establish an experimental animal model of acute myocardial infarction(AMI) in swine;2.To observe the survival and transformation of human embryonic germ cells(hEGCs) inside the infracted swine heart;3. To investigate the expression of fibroblast growth factor(bFGF) after transplanting hEGCs into the myocardium and its significance.Methods:The gonadal ridges from human embryos aged5-10 weeks were taken and cultured in vitro to serve as transplanted cells.2 swine were used in the experiments. On the basis of tracheal intubating, electrocardiogram monitoring and with the help of breathing machine, a model of myocardial infarct in swine was created by the ligation of left anterior descending branch of coronary artery (LAD).With these models successfully being made, 2 swine were divided at random into transplanted group and control group. Transplanted group: hEGCs were transplanted directly to infracted myocardium of the swine. Control group:PBS were injected into the swine in the same way as transplanted group. Specimens were taken at 2 weeks after hEGCs implantation for morphologic examinations. Anti-human nucleus MAB1281 was used as a tracer agent to identify the distribution of transplanted cells and the positive presentation of transcription factors NKx2.5 and TroponinT was observed.To simulate the microenvironment of myocardium by co-culturing hEGCs and human embryo myocardial cells, ABC-ELISA method was used to detect the expression of bFGF in the supernate and compared with that in the hEGCs -alone culture system,and study the expression of bFGF after hEGCs were transplanted into myocardium and its significance.Results:After the ligating of LAD,the changes of electrocardiogram (ECG) and myocardial morphology proved that animal model of AMI in swine was reliable;The results identified by immunohistochemical methods were:with hEGCs being transplanted into infracted myocardium of the swine,the expression of anti-human nucleus MAB1281 was positive and nascent myocardial cells were observed in the infarct site.The expression of NKx2.5 and cTnT was positive in these cells while those in the control group was negative. The expression of bFGF in the supernatant of co-cultured hEGCs and cardiac cells significantly increased, compared with that in culturing hEGCs alone during the same period of time(P<0.05).Conclusions:1. Ligating coronary artery is a valuable method for making animal model of AMI.2. hEGCs transplanted into infracted swine myocardium can remain alive and differentiate into cardiomyocytes.3. Compared with that of culturing hEGCs alone, the expression of bFGF in the supernatant of co-cultured hEGCs and cardiac cell significantly increases,which indicates that the expression of bFGF may notably increase after transplanting hEGCs into the myocardium.This experiment indicates that it is feasible to xenogeneically transplant hEGCs into infracted myocardium.