Abstract:

Objective To observe the expression of AT2R of human bone marrow mononuclear cells (BMMNCs) after the incidence of myocardial infarction (MI) and compare the ability of AT2R+ BMMNCs and AT2R- BMMNCs to protect impaired cardiomyocytes in vitro. Methods The bone marrow were drawn during operation and AT2R+ BMMNCs were isolated by flow cytometer. The migration ability of AT2R+ BMMNCs and AT2R-BMMNCs were compared by Transwell migration detection system with the pore size of 8 μm. The cardiomyocytes of neonatal SD mice were isolated and co-cultured with AT2R+ BMMNCs and AT2R- BMMNCs. The effects of AT2R+ BMMNCs and AT2R- BMMNCs on the transdifferentiation of cardiomyocytes (expressions of transcription factors Nkx2.5 and Gata4 relevant to the cardiac development) were detected by RT-PCR. AT2R+ BMMNCs and AT2R- BMMNCs were co-cultured with cardiomyocytes H9C2 under the conditions of hypoxia and non-serum and the cell apoptosis was detected by flow cytometry. Results Isolation results of flow cytometer showed that the expression of AT2R in bone marrow samples of patients with myocardial infarction was 5.85% higher than that of patients without myocardial infarction (P=0.039 8). In vitro experiment found that the migration ability and the ability of transdifferentiating towards cardiomyocytes of AT2R+ BMMNCs were better than those of AT2R- BMMNCs. Compared with AT2R- BMMNCs, the antiapoptosis effect of AT2R+ BMMNCs on cardiomyocytes H9C2 was stronger under the conditions of hypoxia and non-serum. Conclusion The expression of AT2R in bone marrow of patients with myocardial infarction significantly up-regulates. AT2R+ BMMNCs may protect the cardiomyocytes after the incidence of myocardial infarction.

Key words: bone marrow mononuclear cells, AT2 receptor, migration, transdifferentiation, myocardial infarction