Objective To investigate the effects of granulocyto-colony stimulating factor (G-CSF) on the mobil ization of endothel ial progenitor cells (EPCs) in the rats with myocardial infarction (MI), to observe the density of neovascularization and the mRNA expressions of vascular endothel ial growth factor (VEGF) and its receptor (Flk-1) in the border area of MI. Methods Thirty-six adult male rats (weighing 250-280 g) were divided randomly into control group, MI group, and G-CSF group. In MI group and G-CSF group, the models of MI were establ ished by left anterior descenting coronary artery l igation and were treated with intraperitoneal injection of sal ine (0.3 mL/d) or G-CSF [30 μg/(kg•d)] for 5 days. In control group, after open chest operation, chest was closed without treatment. The level of EPCs was surveyed and the plasma concentrations of VEGF and C-reaction protein (CRP) were measured at 7 days. The mRNA expressions of VEGFand its receptor Flk-1 in the border area of infarct myocardium were determined through RT-PCR. Results Compared withcontrol group, the number of circulating white blood cell (WBC) and EPCs levels, and the serum concentrations of VEGF and CRP were all significantly increased in MI group and G-CSF group (P lt; 0.05); when compared with MI group, the number of circulating WBC and EPCs levels, and the serum concentrations of VEGF were increased and the concentration of CRP was decreased in G-CSF group (P lt; 0.05). Compared with control group, the mRNA expressions of VEGF and Flk-1, and the density of neovascularization in the border area of infarct myocardium were increased in MI group and G-CSF group, whereas those in G-CSF group were significantly augmented compared with MI group (P lt; 0.05). Conclusion In the rats with MI, G-CSF could promote EPCs mobil ization, increase the mRNA expressions of VEGF and Flk-1, and augment the density of neovascularization in the border area of infarct myocardium.
Objective To investigate the effect of simvastatin on inducing endothel ial progenitor cells (EPCs) homing and promoting bone defect repair, and to explore the mechanism of local implanting simvastatin in promoting bone formation. Methods Simvastatin (50 mg) compounded with polylactic acid (PLA, 200 mg) or only PLA (200 mg) was dissolved in acetone (1 mL) to prepare implanted materials (Simvastatin-PLA material, PLA material). EPCs were harvested from bone marrow of 2 male rabbits and cultured with M199; after identified by immunohistochemistry, the cell suspension of EPCs at the 3rd generation (2 × 106 cells/mL) was prepared and transplanted into 12 female rabbits through auricular veins(2 mL). After 3 days, the models of cranial defect with 15 cm diameter were made in the 12 female rabbits. And the defects were repaired with Simvastatin-PLA materials (experimental group, n=6) and PLA materials (control group, n=6), respectively. The bone repair was observed after 8 weeks of operation by gross appearance, X-ray film, and histology; gelatin-ink perfusion and HE staining were used to show the new vessels formation in the defect. Fluorescence in situ hybridization (FISH) was performed to show the EPCs homing at the defect site. Results All experimental animals of 2 groups survived to the end of the experiment. After 8 weeks in experimental group, new bone formation was observed in the bone defect by gross and histology, and an irregular, hyperdense shadow by X-ray film; no similar changes were observed in control group. FISH showed that the male EPC containing Y chromosome was found in the wall of new vessels in the defect of experimental group, while no male EPC containing Y chromosome was found in control group. The percentage of new bone formation in defect area was 91.63% ± 4.07% in experimental group and 59.45% ± 5.43% in control group, showing significant difference (P lt; 0.05). Conclusion Simvastatin can promote bone defect repair, and its mechanism is probably associated with inducing EPCs homing and enhancing vasculogenesis.
Objective To observe the changes in the number and function of bone marrow-derived endothel ial progenitor cells (EPCs) after bone-marrow stimulation, and to investigate the possible mechanism of improving ischemicl imb disease after bone-marrow stimulation through autologue bone-marrow stem cell implantation. Methods Twelvemale Lewis rats, weighing 200-250 g, were classified into the bone marrow stimulation group (n=6) and the control group(n=6). In the stimulation group, the bone marrow of each rat was stimulated by injection of recombinant human granulocytemacrophage colony-stimulatory factor. Mononuclear cells were harvested from bone marrow and cultured in EBM-2 medium. After 7-day culture, EPCs were stained by 1, 1-dioctadecyl-3, 3, 3, 3-tetramethyl indocarbocyanine-labbled acetylated low density l ipoprotein/fluorescein isothiocyanate-ulex europaeus agglutinin 1, and the double positive cells were counted by the fluorescent microscope. The adhesive abil ity of EPCs was determined by counting the number of re-cultured EPCs. The unilateral ischemia hindl imb model was made with 12 Lewis rats. Three days later, EPCs were transplanted into the ischemic tissues. According to different sources of EPCs, the 12 rats were divided into 2 groups: the stimulation group (n=6) and the control group (n=6). At 3 weeks after EPCs transplantation, the quantity of the collateral vascular was observed by digital subtraction angiography (DSA). Results After 7-day culture, the number of EPCs in the stimulation and control groups was (145.2 ± 37.0)/HP and (95.2 ± 39.4)/HP, respectively, and there was significant difference between the two groups (P lt; 0.05). Meanwhile, the number of adhesive EPCs in the stimulation and control groups was (21.8 ± 4.3)/HP and (15.0 ± 5.2)/HP, respectively, and the difference between the two groups was significant (P lt; 0.05). At 3 weeks after the EPCs implantation, the number of the collateral vascular was significantly larger in the stimulation group (4.2 ± 1.2) compared with the control group (2.7 ± 0.8), (P lt; 0.05). Conclusion Bone marrow stimulation increases the number of EPCs and improves the function concurrently, which may be the reason why autologue bone-marrow stem cell implantation improves the curative effect of ischemic l imb diseases after bone-marrow stimulation.