BACKGROUND:The preliminary findings confirm that bone marrow mesenchymal stem celltransplantation is safe and effective in the treatment of acute myocardial infarction, but its exact mechanism is unclear. There are few studies addressing the survival status of transplanted stem cells and its acting timing.
OBJECTIVE:To study the survival of rat bone marrow mesenchymal stem cells transplanted into the infracted myocardium. METHODS:Bone marrow mesenchymal stem cells were cultured using density gradient centrifugation. Eighty rat models of myocardial infarction were prepared. Bone marrow mesenchymal stem cells were injected via a microsyringe at four sites around the infarcted region at 14 days after modeling. Then, 70 rats with living cells were selected for detecting the survival of bone marrow mesenchymal stem cells at days 3, 5, 7, 10, 20, 28 after transplantation. RESULTS AND CONCLUSION:Under ×400 visual field, the number of Brdu-positive bone marrow mesenchymal stem cells was (36±12) at 3 days posttranplantation, (33±13) at 5 days, (28±9) at 7 days, (15±5) at 10 days, (5±3) at 14 days, 0 at 20 days, and 0 at 28 days, showing a overal downward trend after transplantation. The number of bone marrow mesenchymal stem cells was negatively correlated with transplant days (P<0.01, r=-0.47). The number of cells decreased most significantly within 1 week after transplantation, and then decreased to 0 at 20 days. These findings indicate that transplanted bone marrow mesenchymal stem cells in the myocardium cannot survive for a long term and also cannot be transformed into myocardial tissue.