Objective: To observe the effect of simvastatin on the amount and function of endothelial progenitor cells from bone marrow in diabetic rats.
Methods: Experimental study. Twenty male Wistar rats were induced with streptozotocin (STZ) injection for the establishment of diabetic retinopathy model. Mononuclear cells were collected by density gradient centrifugation from the bone marrow of rats. The isolated cells were cultivated in dishes coated with fibronectin. Cultured cells were divided into normal control (CON) group and the intervention group. Cells in the CON group were cultured with regular culture medium and the intervention group was treated with 0.01, 0.1, 1 and 10 µmol/L of simvastatin. Immuno-fluorescence staining and flow cytometry were used to identify EPC. The colony number of EPC was assayed by CFU counting. Proliferation, migration and adhesion function of EPC were assayed by MTT chromatometry, modified Boyden chamber assay and adhesion activity assay, respectively. All eyeballs were examined by histopathological examination stained by hematoxylin and eosin (HE) and electron microscopic examination. The amount, proliferation, migration and adhesion function of EPC were analyzed by one-way ANOVA and LSD-t methods.
Results: The cell clusters number of bone marrow-derived EPC was significantly increased in intervention groups [(16.5 ± 1.6), (19.0 ± 2.3), (21.9 ± 2.0), (13.9 ± 2.4) n/200 fields in cultures treated with 0.01, 0.1, 1 and 10 µmol/L of simvastatin] compared with that in the CON group [(14.0 ± 2.4) n/200 fields]. The proliferation ability of EPC was increased in intervention groups (0.105 ± 0.014, 0.133 ± 0.024, 0.202 ± 0.039 and 0.068 ± 0.011) compared with that in the CON group (0.072 ± 0.011). The migration ability of EPC was increased in intervention groups [(10.5 ± 1.6), (12.9 ± 2.2), (15.9 ± 2.4), (9.4 ± 1.4) cells/200 fields] compared with that in the CON group [(8.9 ± 1.2) cells/200 fields]. The adhesion ability of EPC was increased in intervention groups [(10.6 ± 1.9), (15.1 ± 2.7), (19.0 ± 3.9), (7.9 ± 1.2) cells/200 fields] compared with that in the CON group [(7.5 ± 1.2) cells/200 fields]. The thickness of retina was reduced and retinal cells became disorganized in diabetic rats. Transmission electron microscopy showed capillary lumen stenosis and retinal microaneurysms with severe local tissue ischemia such as vacuolar degeneration perivascular tissue.
Conclusion: Simvastatin can enhance the amount and function of EPC from bone marrow in diabetic rats in a dose-dependent manner.