ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of recombinant human interleukin-2 (rhIL-2) activated natural killer cells (rhIL-2-NK) on angiogenesis and cardiac function of rats with myocardial infarction (MI).</p><p><b>METHODS</b>Natural killer cells (NKs) were isolated and activated by rhIL-2 in vitro. Untreated NKs were used as the control, the killing capacity of rhIL-2-NK were evaluated with cytotoxicity assay. Cardiac microvascular endothelial cells (CMECs) were cocultured with rhIL-2-NK. One hour after MI, rats were randomly divided into rhIL-2-NK group, NK group and blank control group and NK, rhIL-2-NK and PBS were injected directly in the infracted myocardium. At the 0, 1(st), 3(rd), 5(th), 7(th) and 20(th)th day after MI, the mRNA expression of monocyte chemotactic protein-1 (MCP-1), Tumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2) were was detected by q-PCR essay. At the end of the therapy, the platelet endothelial cell adhesion molecule-1(CD31) and vascular endothelial growth factor (VEGF) were evaluated through immunohistochemical assay, and the cardiac function observed with echocardiography, homodynamic measurements.</p><p><b>RESULTS</b>The NKs were isolated successfully and the CMEC were proliferated remarkably by coculturing with rhIL-2-NK (P < 0.01). The mRNA expression of MCP-1, TNF-α, CD31 and rhIL-2, VEGF were significantly upregulated in rhIL-2-NK group than in the PBS control group (P < 0.01). Four weeks after operation, LVEF was significantly higher in rhIL-2-NK group than in the PBS control group [(77.56 ± 15.67)% vs. (41.47 ± 12.21)%, P < 0.05)] and histomorphology assay revealed that the density of microvascular endothelial (MVD) of rhIL-2-NK group was significantly higher than that of PBS control group (17.35 ± 1.82 vs. 4.76 ± 0.92, P < 0.01).</p><p><b>CONCLUSIONS</b>Myocardial injection of rhIL-2-NK could promote angiogenesis and improve cardiac function in MI rats.</p>