Oyama Tomokazu, Miyasita Yoh, Watanabe Husako, Shirai Kohji
Center of Diabetes, Endocrine and Metabolism, Sakura Hospital, School of Medicine, Toho University, 564-1 Shimoshizu, Sakura-City, Chiba, Japan.
Diabetes Res Clin Pract. 2006 Sep;73(3):227-34. doi: 10.1016/j.diabres.2006.02.010. Epub 2006 Apr 19.
To clarify the mechanism by which hyperglycemia in diabetes mellitus causes endothelial cell damages, the effects of high glucose on DNA fragmentation and caspase-3 activity of cultured endothelial cells and on the generation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) were studied. Furthermore, the involvement of the polyol pathway in this process was investigated using aldose reductase inhibitor (SNK-860). Human umbilical vein endothelial cells (HUVECs) were incubated with 5.5mmol/L (low glucose medium) or 28mmol/L (high glucose medium) of glucose. The amounts of fragmented DNA, caspase-3 activity and 8-OHdG in the medium increased in significantly greater extent in high glucose-incubated HUVECs than in low glucose-incubated HUVECs. No significant increase in fragmented DNA or 8-OHdG was observed when HUVECs were incubated with mannitol (500mg/mL). The concentration of intracellular sorbitol was significantly higher in HUVECs incubated in high glucose medium than that in low glucose medium. Addition of the aldose reductase inhibitor SNK-860 dose-dependently decreased the intracellular sorbitol concentration in HUVECs incubated in high glucose medium, and also significantly suppressed the increases in fragmented DNA, caspase-3 activity and 8-OHdG by conditioning with high glucose medium. These results suggest that high glucose-induced endothelial cell damages may be mediated by activation of the polyol pathway accompanied by augmented oxidative stress.
为阐明糖尿病中的高血糖导致内皮细胞损伤的机制，研究了高糖对培养的内皮细胞DNA片段化和半胱天冬酶-3活性以及8-羟基-2'-脱氧鸟苷（8-OHdG）生成的影响。此外，使用醛糖还原酶抑制剂（SNK-860）研究了多元醇途径在这一过程中的作用。人脐静脉内皮细胞（HUVECs）分别在含5.5mmol/L（低糖培养基）或28mmol/L（高糖培养基）葡萄糖的条件下培养。与低糖培养的HUVECs相比，高糖培养的HUVECs培养基中DNA片段、半胱天冬酶-3活性和8-OHdG的增加幅度显著更大。当HUVECs与甘露醇（500mg/mL）一起培养时，未观察到DNA片段或8-OHdG有显著增加。高糖培养基中培养的HUVECs细胞内山梨醇浓度显著高于低糖培养基中的浓度。添加醛糖还原酶抑制剂SNK-860可剂量依赖性降低高糖培养基中培养的HUVECs细胞内山梨醇浓度，并且还显著抑制了高糖培养基处理导致的DNA片段、半胱天冬酶-3活性和8-OHdG的增加。这些结果表明，高糖诱导的内皮细胞损伤可能是由多元醇途径的激活介导的，同时伴有氧化应激增强。
