在糖尿病的高葡萄糖環境下，可發現有自由基增加及抗氧化系統失衡的情形產生，所引發的氧化傷害進而會造成如：糖尿病腎病變、視網膜病變…等血管細胞增生併發症。尿酸在之前的報告中曾被提及具有抗氧化的特性，因此本實驗即在探討尿酸與公認的抗氧化物質─維生素C、E，對高葡萄糖下內皮細胞胞外間質( ECM )蛋白質之影響。實驗方法是將人類臍靜脈內皮細胞( HUVEC )培養於不同濃度的葡萄糖( 0、5、10、30 mM )，尿酸( 3、5、10 mg/dl )，維生素C、E( 0.05 mM )下，72小時後分別以酵素連結免疫吸附法( ELISA )及西方點漬法( Western blotting )分析各組細胞內纖維網狀蛋白、Laminin及糖化終產物( AGEs )的含量。結果顯示：隨著葡萄糖濃度增加，AGEs的形成也隨之增加，而內皮細胞中的間質蛋白纖維網狀蛋白會降低、基底膜組成份Laminin增加。添加維生素E會增加纖維網狀蛋白的含量，但會降低高葡萄糖下細胞中的Laminin及AGEs。維生素C、尿酸則會同時降低高葡萄糖下內皮細胞中的纖維網狀蛋白、Laminin和AGEs。另外，將尿酸與維生素C共同添加則會更明顯地降低AGEs。由結果可得知，尿酸的確可與維生素C、E一樣擔任抗氧化的角色，進而將高葡萄糖造成的AGEs降低。內皮細胞中基底膜Laminin的生成會受AGEs所調控，而纖維網狀蛋白則非。
The elevation of the free radical and the unbalance of the antioxidative systems in diabetes are correlated with the complication of diabetic nephropathy and retinopathy. It has been reported that uric acid seems to be an antioxidant. Therefore, this study is designed to investigate the effects of uric acid and the putative antioxidants─vitamin C, E on ECM of endothelial cells under high glucose state. The exposure of human umbilical vein endothelial cells ( HUVEC ) to glucose ( 0, 5, 10, 30 mM ), uric acid ( 3, 5, 10 mg/dl ) and vitamin C, E ( 0.05 mM ) for 72 h experiments, after then measured the fibronectin, laminin and AGEs contents by ELISA and western blotting respectively. High glucose induced AGEs formation, decrease fibronectin and increase laminin in endothelial cells. The addition of vitamin E to HUVEC cultured in high glucose increased fibronectin synthesis but not laminin and AGEs. Lower contents of fibronectin, laminin and AGEs were observed in HUVEC cultured on glucose and vitamin C, Uric acid. A combination of vitamin C and uric acid exhibits a significant AGEs decreased. This results suggest that uric acid works as antioxidants likes vitamin C, E and decreased AGEs in HUVEC. The synthesis of basement membrane laminin in HUVEC is modulated by AGEs, but not the extracellular matrix fibronectin.
