Preliminary Study on the Mechanism of Acupoint Injection of BoneMarrow Mesenchymal Stem Cells in Improving Blood Flow in the Rat of Hind Limb Ischemia

OBJECTIVE: To explore the mechanism of acupoint injection of bone marrow mesenchymal stem cells (BM-MSCs) in improving blood flow in the rat with hind limb ischemia. METHODS: Twenty-four SD rats were randomly divided into 4 groups: normal control group (n = 6), model group (n = 6), BM-MSCs acupoint injection group (AI group, n = 6) and BM-MSC intramuscular injection group (MI group, n = 6). Sanyinjiao (SP 6), Housanli (ST 36), Zhaohai (KI 6), Huantiao (GB 30) and Yanglingquan (GB 34) were selected for the AI group, and five non-acupoints were selected on gastrocnemius and adductor of ischemic hind limbs in the MI group. BM-MSCs were injected to the latter two groups. The rat hind limb ischemia model was established with the method of blocking the femoral artery and its branches. Three weeks after injection of BM-MSCs, in each group, hindlimb adductor and gastrocnemius were taken from the ischemic side. Expressions of vascular endothelial growth factor (VEGF) and transfer growth factor-beta1 (TGF-beta1) in the skeletal muscle were determined with immunohistochemical method, and the small arteries in the skeletal muscle were labeled with alpha-SMA immunohistochemical staining method, the density of small arteries (number of arterioles/number of muscle fibers) and the number of the blood vessel with VEGF positive expression were calculated. The serum levels of VEGF and nitric oxide (NO) were detected. RESULTS: Compared with the model group, the expression of VEGF and TGF-beta1, and the density of small arteries and the number of VEGF-positive blood vessels in the AI group and the MI group significantly increased (both P < 0.01). Compared with the MI group, the density of small arteries and the number of VEGF-positive blood vessels in the AI group significantly increased (both P < 0.01); Compared with the model group and the normal control group, the serum expression quantity of NO and VEGF in the AI group and the MI group were significantly increased (P < 0.01). CONCLUSIONS: Acuppoint injection of BM-MSCs secrets more VEGF, TGF-beta1 and NO to increase angiogenesis and arteriogenesis, so as to improve blood flow of the rats of hind limb ischemic.