Fig. 6

Transplantation of VCAM-1⁺CV-MSCs significantly enhanced the blood perfusion and the generation of collateral vessels in the ischemic sites. a VCAM-1^+/−CV-MSCs or PBS were injected into the ischemic site of nude mice. Percentage distributions of limb salvage, foot necrosis, and limb loss in the three groups are shown and analyzed by the Fisher’s exact test (n = 11, p = 0.102). Ischemia damage and physiological function of ischemic limbs were semiquantified by ischemia scores b and ambulatory impairment scores c (n = 11, *p <0.05). d Blood perfusion in ischemic/healthy limb was detected by the Kodak In-Vivo FX Pro Imaging System on days (D) 0, 7, and 20. Different colors indicate different blood perfusion. Blood flow increased from dark blue to red. e Blood perfusion ratio in ischemic to healthy limbs was used to quantitatively analyze the blood flow restoration in ischemic limbs (n = 11, *p <0.05, **p <0.01). f Angiography was performed to assess the collateral vessel generation in the ischemic site. Red curves indicated the site of the femoral arteries incision; black arrows showed the collateral vessels in the ischemic hind limb. g Angiography score indicated that VCAM-1⁺CV-MSCs were superior to VCAM-1⁻CV-MSCs in augmenting collateral vessels (n = 3–5, *p <0.05). h H & E staining was performed to study the vessel density in ischemia limbs. Pictures showed that the blood vessels were full of barium sulfate (silver, scale bar = 100 μm). i Vessel density in VCAM-1⁺CV-MSC or VCAM-1⁻CV-MSCs group was significantly greater than the PBS group (n = 7, ***p <0.001, ****p <0.0001). Furthermore, VCAM-1⁺CV-MSC transplantation apparently promoted the vessel generation compared with the VCAM-1⁻CV-MSCs group (**p <0.05). CV chorionic villi, MSC mesenchymal stem cell, PBS phosphate-buffered saline, VCAM-1 vascular cell adhesion molecule 1 (Color figure online)