[Effect of intracoronary autologous bone marrow mononuclear cells transplantation on arrhythmia in canines].

To observe the survival and the differentiation of grafted bone marrow cells (BM-MNCs) in host myocardium. To observe whether BM-MNCs transplantation can potentially cause arrhythmia and whether the BM-MNCs transplantation can alter the spatial distribution of connexins, important mediator for arrhythmia genesis after myocardial infarction. Acute myocardial infarction (AMI) was induced by left anterior descending coronary artery (LAD) ligation in hybrid canine. BM-MNCs suspension was prepared by density centrifugation. The BM-MNCs were labeled with CM-DiI. Sixteen hybrid canines were randomly divided into transplantation group and control group. BM-MNCs (transplantation group, =10) or saline (control group, =6) were intracoronarily infused into infarction related artery at 2 hours after AMI. At 6 weeks after AMI, ventricular fibrillation (VF) was induced in infarct area and periinfarct area. The effective refractive period (ERP) of different areas in myocardium was assessed and the expression of connexin 43 (Cx43) was assessed by immunohistochemical staining. Six weeks after the BM-MNCs transplantation, CM-DiI labeled BM-MNCs were mainly located within periinfarct and infarct area. Some BM-MNCs were positive for Cx43. Combined" CM-DiI and FITC" in images were observed. VF was induced in 2 out of the 10 canines in transplantation group and in 2 out of the 6 canines in control group in infarct area. VF was not induced in periinfarct area of both groups. The ERP of infarct area ((85.0±9.3) ms vs. (90.0±7.1)ms, >0.05), periinfarct area (87.8±9.4 vs. 90.0±7.1, >0.05) and normal area (85.0±12.0 vs. 88.3±9.4, >0.05) was similar between transplantation group and control group. The expression of Cx43 in normal area was similar between transplantation group and control group (3 543.7±446.0 vs. 3 431.7±421.5, >0.05). The expression of Cx43 in periinfarct area of transplantation group was significantly higher than that in control group (2 312.5±412.0 vs. 1 356.2±332.7, <0.05), but was still much less than in normal area (2 312.5±412.0 vs. 3 543.7±446.0, <0.05). The expression of Cx43 in infarct area was similar between transplantation group and control group (327.0±98.7 vs. 311.3±78.7, >0.05). The implanted BM-MNCs could survive in the infarcted lesion and differentiate into cells expressing Cx43.In transplanted group, VF was not induced in periinfarct area. ERP of infarct area, periinfarct area and normal area is similar between two groups. The expression of Cx43 in periinfarct area was significantly higher in transplantation group than that in control group.