Geetha A, Surendran R
Post Graduate Department of Biochemistry, Bharathi Women's College, North Chennai, Tamil Nadu, India.
Pharmazie. 2005 Aug;60(8):609-13.
The aim of this study was to investigate copper (Cu++) induced oxidation state of LDL isolated from obstructive jaundice (OBJ) patients with hyperlipidemia and the effect of UDCA on the same. LDL was isolated and oxidation was induced by 5 mM CuSO4 with/without UDCA at different concentrations. LDL oxidation was assessed at different time intervals in terms of conjugated dienes, hydroperoxides and 'thiobarbituric acid reacting substances' (TBARS). The change in the level of endogenous LDL alpha-tocopherol was also monitored simultaneously. The oxidisability of LDL isolated from OBJ patients was significantly higher and showed a steep increase in the level of conjugated diene formation without any lag phase. In normal samples the oxidation proceeded slowly with a lag phase. This was also evidenced by the level of formation of hydroperoxides and TBARS. The basal level of LDL alpha-tocopherol was significantly low in OBJ samples. UDCA was found to delay the oxidation of LDL in a dose dependent manner. The consumption of alpha-tocopherol was found to be minimum in the presence of UDCA. The results of this investigation show that there is a high susceptibility of LDL to oxidation in OBJ cases and this may be due to low endogenous LDL alpha-tocopherol content. UDCA minimizes LDL oxidation in dose dependent manner, which is an additional evidence for its antioxidant nature.
本研究旨在调查铜离子（Cu++）诱导的阻塞性黄疸（OBJ）高脂血症患者低密度脂蛋白（LDL）的氧化状态以及熊去氧胆酸（UDCA）对其的影响。分离LDL，并在有/无不同浓度UDCA的情况下，用5 mM硫酸铜诱导其氧化。在不同时间间隔，根据共轭二烯、氢过氧化物和“硫代巴比妥酸反应物质”（TBARS）评估LDL氧化情况。同时监测内源性LDLα-生育酚水平的变化。从OBJ患者分离的LDL的氧化能力显著更高，并且共轭二烯形成水平急剧增加，没有任何延迟期。在正常样本中，氧化过程缓慢且有延迟期。氢过氧化物和TBARS的形成水平也证明了这一点。OBJ样本中LDLα-生育酚的基础水平显著较低。发现UDCA以剂量依赖性方式延迟LDL的氧化。发现在有UDCA存在的情况下，α-生育酚的消耗最少。本研究结果表明，OBJ病例中LDL对氧化高度敏感，这可能是由于内源性LDLα-生育酚含量低所致。UDCA以剂量依赖性方式使LDL氧化最小化，这是其抗氧化性质的又一证据。
