Bhaskar L, Balasubramanian K A
Wellcome Research Laboratory, Christian Medical College Hospital, Vellore, India.
Indian J Biochem Biophys. 1995 Apr;32(2):89-93.
Effects of various oxidants on the colonic membrane lipid peroxidation have been studied in rats. 2,2-Azobis (2-amidinopropane) dihydrochloride (ABAP), which generates free radicals by thermal decomposition, induced peroxidation as judged by the formation of conjugated diene, malondialdehyde (MDA), and depletion of arachidonic acid. Exposure to other oxidants which require free iron for peroxidation was ineffective. Alpha tocopherol level was not altered on exposure to various oxidants except with ABAP which depleted its level in these membranes. Exposure of the membranes to both ABAP and xanthine-xanthine oxidase (X-XO) decreased total protein thiols, whereas other oxidants had no significant effect. Isolated colonocyte membranes were found to contain considerable amount of nonesterified fatty acids as part of the total lipids and removal of free fatty acids from the membrane using fatty acid-free albumin made the membranes susceptible to iron-induced free radical generation and lipid peroxidation. These studies suggest that colonocytes are possibly protected from lipid peroxidation by the free fatty acids associated with the membrane.
在大鼠中研究了各种氧化剂对结肠膜脂质过氧化的影响。2,2-偶氮双（2-脒基丙烷）二盐酸盐（ABAP）通过热分解产生自由基，根据共轭二烯、丙二醛（MDA）的形成以及花生四烯酸的消耗判断其诱导了过氧化。暴露于其他需要游离铁进行过氧化的氧化剂则无效。除了ABAP使这些膜中的α-生育酚水平降低外，暴露于各种氧化剂时α-生育酚水平未改变。将膜暴露于ABAP和黄嘌呤-黄嘌呤氧化酶（X-XO）均会降低总蛋白巯基，而其他氧化剂则无显著影响。发现分离的结肠细胞膜含有相当数量的非酯化脂肪酸作为总脂质的一部分，使用无脂肪酸白蛋白从膜中去除游离脂肪酸会使膜易受铁诱导的自由基生成和脂质过氧化的影响。这些研究表明，结肠细胞可能受到与膜相关的游离脂肪酸的保护而免受脂质过氧化。
