Abstract:

Objective To observe the effects of high concentration glucose and advanced glycation end products (AGEs) on wound closure, formation ability of vascular-like structure, and the expression of relevant regulatory factor of vascularization of vascular endothelial cells cultured in vitro. Methods Human umbilical vein endothelial cells (HUVECs) cultured in vitro were divided into the high concentration glucose group (30 mmol/L of D-glucose), AGEs group (150 mg/L of AGEs-BSA), high concentration glucose+AGEs group (30 mmol/L of D-glucose+150 mg/L of AGEs-BSA), normal group (5 mmol/L of D-glucose) according to different concentrations of glucose and AGEs-BSA added in the culture fluid, and the mannitol group (30 mmol/L of mannitol). The proliferation curve of injury model of HUVECs was detected by the electric cell-substrate impedance sensing (ECIS). The formation of vascular-like structure of HUVECs in Matrigel matrix was observed by the inverted microscope. The expressions of vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang-2) in cell culture supernatants were detected by the ELISA and the expression of Tie-2 receptor in HUVECs was observed by the fluorescence microscope. Results The results of ECIS showed that proliferation curves of HUVECs of each group were similar and differences of their slopes, which represented the healing rate, were not significant. Observations of the inverted microscope found that lengths of formed vascular-like structures of the high concentration glucose group, AGEs group, and high concentration glucose+AGEs group were significantly shorter than those of the normal group (P<0.05 or P<0.01). The results of ELISA indicated that expressions of the Ang-2 levels in cell culture supernatants of the high concentration glucose group, AGEs group, and high concentration glucose+AGEs group were significantly higher than those of the normal group and expressions of the VEGF levels were significantly lower (P<0.05). Observations of the fluorescence microscope showed that Tie-2 receptors were expressed in the cytomembrane and cytoplasm of HUVECs of the normal group and were only expressed in the nucleolus of HUVECs of the AGEs group. Conclusion High concentration glucose and/or AGEs can inhibit the formation ability of vascular-like structure of vascular endothelial cells. The mechanism may be relevant to the up-regulation of Ang-2, down-regulation of VEGF, and the differential expression of Tie-2 receptor in different locations of cells.

Key words: glucose, advanced glycation end product, angiogenesis, endothelial cell