Effect of “Xiaoke Tongbi granule” on the proliferation, migration and tubule-forming ability of rat endothelial progenitor cells under high glucose conditions

Purpose: To investigate the effect of Xiaoke Tongbi granule (XTG) on the proliferation, migration and tubule-forming ability of endothelial progenitor cells (EPCs) of rats under high glucose conditions. Methods: Six specific pathogen-free (SPF) and twenty-four healthy rats (mean weight = 200 ± 20 g) were used in this study. Twenty-four (24) healthy rats were treated with graded concentrations of XTG (0.75 – 2.25 g/mL) for 7 days, and were thereafter euthanized to obtain serum which was later used to treat EPCs isolated from bone marrow of SPF rats. The EPCs were seeded in culture plates pre-coated with human fibronectin, and cultured at 37 °C for 72 h in a humidified atmosphere of 5 % CO2 and 95 % air. Cell viability and apoptosis were assessed using 3 (4,5 dimethyl thiazol 2 yl) 2,5 diphenyl 2H tetrazolium bromide (MTT), and flow cytometric assays, respectively. The morphology of isolated EPCs was assessed by immunofluorescence. Results: The isolated EPCs exhibited normal morphology, and were CD34-positive. Proliferation and migration of EPCs, and number of tubular structures formed were significantly suppressed under high glucose conditions, but were significantly and concentration-dependently promoted by XTG treatment (p < 0.05). Treatment with XTG also significantly improved the morphology of isolated EPCs (p < 0.05). Apoptosis was significantly promoted by high glucose conditions, but was significantly and concentration-dependently reduced by XTG treatment (p < 0.05). The incidence of tubule formation in high glucose group was 0.63 %, but was progressively increased from 1.37 to 1.52 % after treatment with graded concentrations of XTG. Conclusion: These results indicate that XTG reverses the effect of high glucose environment on EPC proliferation, migration and tubule-forming ability.