Chunxiao Wan, Jianan Li, Lihua Yi
DOI: 10.2340/16501977-0815

Objective: To investigate the effects of physiological ischaemia training on the quantity and activity of endothelial progenitor cells in rabbits with intermittent myocardial ischaemia.
Methods: A reversible coronary artery water balloon occluder (5. 0 mm inner diameter) was placed around the proximal left ventricular branch and intermittent myocardial ischaemia was induced by deflation and inflation of the occluder. A wire electrode was inserted longitudinally into the epineurium of the sciatic nerve to generate physiological ischaemia training through isometric contraction induced by electrical stimulation. Rabbits were randomly divided into 3 groups: a sham operated group (SO), an intermittent myocardial ischaemia-only group (MI), and an MI plus physiological ischaemia training group (PT). Intermittent myocardial ischaemia was induced with 2-min ischaemia followed by 1-h reperfusion. Physiological ischaemia training was induced by electrical stimulation (40% maximum current strength, 1 ms, 40 Hz), 4-min per session, twice a day, 5 days per week for 4 weeks. At the end-points, endothelial progenitor cells were isolated and cultured for analysis of their migration ability. Endothelial progenitor cells were identified by dual-staining with Dil-labelled acetylated low-density lipoprotein and fluorescein isothiocyanate-labelled Ulex europaeus agglutinin-1. Circulating endothelial progenitor cells (CD34+/Flk-1+) were counted by fluorescence-activated cell sorter, and capillary density was evaluated by immunohistochemistry examination.
Results: Group PT showed the highest migration capacity of endothelial progenitor cells (151 cells, standard deviation 16/high power field) and the highest increase in circulating endothelial progenitor cells (p < 0. 01) after 4 weeks’ physiological ischaemia training. Capillary density in the myocardium was also significantly enhanced in group PT (p < 0. 05). Pearson’s analysis demonstrated a positive correlation between the number circulating endothelial progenitor cells and capillary density in the myocardium after 4 weeks’ physiological ischaemia training (p < 0. 05).
Conclusion: Physiological ischaemia training may enhance the quantity and activity of endothelial progenitor cells in the blood, resulting in an increase in angiogenesis in the ischaemic heart region.