Intra-Arterial Bone Marrow Cell Transplantation Induces Angiogenesis in Rat Hindlimb Ischemia

Abstract

Background: Bone marrow (BM) cells have been shown to augment local angiogenesis by differentiating vessels themselves and/or secreting paracrinally angiogenic growth factors. Herein, the angiogenic effects of intra-arterial BM mononuclear cell (BM-MNC) transplantation were evaluated in a rat ischemic hindlimb model. Methods: Unilateral hindlimb ischemia was created by excising the femoral artery and its branch in Lewis rats. BM-MNCs were isolated by centrifugation through a Histopaque density gradient. One week after excision of the unilateral femoral artery, BM-MNCs (5 × 10⁶ cells, Group A, n = 6) or PBS (Group B, n = 7) were injected into the ischemic thigh skeletal muscles at the six points with a gauge needle. Another injection of BM-MNCs (3 × 10⁷ cells, Group C, n = 6) or PBS (Group D, n = 7) was administered via the indwelling catheter in the right common iliac artery. Results: Four weeks after the BM-MNC transplantation, angiographic examination revealed the development of collateral vessels in both BM-MNC-transplanted groups. The difference in skin temperature between right and left hindlimbs was significantly reduced in both BM-MNC-transplanted groups (0.93 ± 0.15 vs. 2.84 ± 0.35 vs. 1.20 ± 0.26 vs. 2.61 ± 0.37°C, Group A vs. Group B vs. Group C vs. Group D, p < 0.05). Moreover, immunohistochemical analysis demonstrated that capillary endothelial cells were increased in both BM-MNC-transplanted groups. Conclusion: BM-MNC implantation was able to induce functional neovascularization in rat ischemic hindlimb. The intra-arterial administration offered similar levels of angiogenic activity as intramuscular injection.