Autologous implantation of bone marrow mononuclear cells at differe nt times after myocardial infarction

Objective To investigate t he ability of bone marrow mononuclear cells (BM-MNCs) for improving damaged hea rt function and explore the optimal delivery period.Methods After the left anterior descending of coronary artery ligation, BM-MNCs isolate d from adult rabbits'(n=35) tibias labeled with bromodeoxyuridine were inje cted into the LAD risk area after myocardial infarction at 1week, 2 weeks,4 week s, 8 weeks and 12 weeks, respectively.The animals were killed at 4 weeks after implantation.The left ventricular functions and infarct size were measured, and the differentiation of the engrafted cells were determined by immunostaining. Results Immunohistochemical results showed that autologou s implantation of BM-MNCs in the hearts can express cardiac specific troponin T , factor Ⅷ, smooth muscle α-actin and connexin-43. Compared with the sham-o perated group, left ventricular systolic functions including ejection fraction, the ΔD(D_d minus Ds)to D_d, LV+dp/dt_ max and LV-dp/dt _ max and the infarct size were significantly improved at all BM-MNCs impla ntation groups. Furthermore, LV performance and infracted area were significantl y better in the MNCs-treated groups during 4 weeks after MI than do it at 8 wee ks, 12 weeks after MI. Conclusion BM-MNCs transplantation at myocardial infarction would result in a decrease in the infarct size and an increase in the heart function. Moreover, implantation o f MNCs during 4 weeks after MI can receive a better gain in heart function and i nfarct size.