Bone marrow stem cell mobilization and cytokines expression in ischemic myocardium in diabetic rats with myocardial ischemia

Objective: To investigate the bone marrow stem cell mobilization and homing changes of peripheral blood due to diabetic myocardial ischemia in rats and the change of expression of the vascular endothelial growth factor (VEGF) and the tumor necrosis factor α (TNFα) in ischemic myocardial tissue. Methods: The diabetic model of male Sprague-Dawley rats was created by intraperitoneal injection of streptozotocin first. Then the diabetic myocardial ischemia model was established through ligation of the left anterior descending coronary artery. The rats were divided into ischemic day-1, day-3, day-7, and day-28 groups. And their time-matching diabetic sham operation control group and normal sham operation control group were also established, with 6 rats in each group. Flow cytometry was used to measure the percentage of CD34⁺ cells in peripheral blood mononuclear cells for each group. Immunohistochemistry was used to observe the homing of CD34⁺ cells and the expression of VEGF and TNFα in the ischemic myocardium. Results: The mobilization of bone marrow stem cells was initiated after the surgery in the rat models of myocardial ischemia in diabetes and it peaked within 1 week and decreased with the passage of time. Accordingly the homing of CD34⁺ cells and the expressions of VEGF and TNFα in the ischemic myocardium were significantly increased. Conclusion: During the early stage, the diabetic ischemic myocardium can mobilize bone marrow stem cells into the peripheral blood and start homing to the ischemic myocardium by increasing VEGF and TNFα in the ischemic myocardium, thereby initiating the self-protection mechanisms.