Palacios Alejandro, Piergiacomi Viviana, Catalá Angel
Cátedra de Bioquímica, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina.
Mol Cell Biochem. 2003 Aug;250(1-2):107-13. doi: 10.1023/a:1024977613141.
In the study reported here the effect of conjugated linoleic acid (CLA) and vitamin A on the polyunsaturated fatty acid composition, chemiluminescence and peroxidizability index of microsomes and mitochondria isolated from rat liver was analyzed. The effect of CLA on the polyunsaturated fatty acid composition of native microsomes was evidenced by an statistically significant p < 0.007 decrease of linoleic acid C18:2 n6, whereas in mitochondria it was observed a decrease p < 0.0001 of arachidonic acid C20:4 n6 when compared with vitamin A and control groups. Docosahexaenoic acid C22:6 n3 in mitochondria was reduced p < 0.04 in CLA and vitamin A groups when compared with control. After incubation of microsomes or mitochondria in an ascorbate (0.4 mM)-Fe++ (2.15 microM) system (120 min at 37 degrees C) it was observed that the total cpm/mg protein originated from light emission: chemiluminescence was lower in liver microsomes or mitochondria obtained from CLA group (received orally: 12.5 mg/daily during 10 days) than in the vitamin A group (received intraperitoneal injection: daily 0.195 g/ kg during 10 days). CLA reduced significantly maximal induced chemiluminescence in microsomes relative to vitamin A and control groups, whereas in mitochondria the effect was observed relative to control group. The polyunsaturated fatty acid composition of liver microsomes or mitochondria changed by CLA and vitamin A treatment. The polyunsaturated fatty acids mainly affected when microsomes native and peroxidized from control group were compared were linoleic, linolenic and arachidonic acids, while in vitamin A group linoleic and arachidonic acid were mainly peroxidized, whereas in CLA group only arachidonic acid was altered. In mitochondria obtained from the three groups arachidonic acid and docosahexaenoic acid showed a significant decrease when native and peroxidized groups were compared. As a consequence the peroxidizability index, a parameter based on the maximal rate of oxidation of fatty acids, show significant changes in the CLA group compare vitamin A and control groups. The simultaneous analysis of peroxidizability index, chemiluminescence and fatty acid composition demonstrated that CLA is more effective than vitamin A protecting microsomes or mitochondria from peroxidative damage.
在本研究中，分析了共轭亚油酸（CLA）和维生素A对从大鼠肝脏分离的微粒体和线粒体的多不饱和脂肪酸组成、化学发光和过氧化能力指数的影响。CLA对天然微粒体多不饱和脂肪酸组成的影响表现为亚油酸C18:2 n6显著降低（p < 0.007），而在与维生素A和对照组相比的线粒体中，花生四烯酸C20:4 n6降低（p < 0.0001）。与对照组相比，CLA和维生素A组线粒体中的二十二碳六烯酸C22:6 n3降低（p < 0.04）。在微粒体或线粒体于抗坏血酸盐（0.4 mM）-Fe++（2.15 microM）系统中孵育（37℃ 120分钟）后，观察到每毫克蛋白质源自发光的总cpm：CLA组（口服给药：12.5毫克/天，持续10天）的肝脏微粒体或线粒体中的化学发光低于维生素A组（腹腔注射给药：0.195克/千克/天，持续10天）。与维生素A和对照组相比，CLA显著降低了微粒体中最大诱导化学发光，而在与对照组相比的线粒体中观察到了这种效果。CLA和维生素A处理改变了肝脏微粒体或线粒体的多不饱和脂肪酸组成。当比较对照组天然和过氧化的微粒体时，主要受影响的多不饱和脂肪酸是亚油酸、亚麻酸和花生四烯酸，而在维生素A组中亚油酸和花生四烯酸主要被过氧化，而在CLA组中只有花生四烯酸发生了改变。在比较三组来源的线粒体天然和过氧化组时，花生四烯酸和二十二碳六烯酸显著降低。因此，基于脂肪酸最大氧化速率的过氧化能力指数在CLA组与维生素A和对照组相比时显示出显著变化。过氧化能力指数、化学发光和脂肪酸组成的同步分析表明，CLA在保护微粒体或线粒体免受过氧化损伤方面比维生素A更有效。
