CHARACTERIZATION OF IRON-MEDIATED PEROXIDATIVE INJURY IN ISOLATED HEPATIC LYSOSOMES
CHARACTERIZATION OF IRON-MEDIATED PEROXIDATIVE INJURY IN ISOLATED HEPATIC LYSOSOMES
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DOI：
10.1172/jci111697
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发表时间：
1985-01-01
影响因子：
15.9
通讯作者：
WEGLICKI, WB
中科院分区：
文献类型：
--
作者：
MAK, IT;WEGLICKI, WB
溶酶体膜的过氧化降解和由此产生的水解酶的释放可能是铁毒性肝细胞损伤的原因。高纯度肝溶酶体体外暴露于铁盐；研究了铁介导的损伤过程的性质和溶酶体完整性的易感性。用自由流动电泳法分离大鼠肝溶酶体。溶酶体37度孵育。C与Fe3+-ADP在抗坏血酸存在下导致丙二醛[MDA]的快速生成，在20分钟时接近平台。溶酶体潜伏期的减少，以n -乙酰基- β游离活性百分比的增加来确定。-氨基葡萄糖苷酶也出现，并在30min时达到最大损失。促进Fe3+-ADP介导的溶酶体过氧化所需的抗坏血酸的一半最大水平约为。10 .mu.M;高浓度的抗坏血酸具有抑制作用，在浓度为2 mM时达到半最大抑制作用。铁介导的溶酶体过氧化反应不受大多数活性氧清除剂的抑制，似乎只依赖于Fe2+物种的产生。当新鲜的Fe2+溶液与溶酶体孵育时，脂质过氧化程度和潜伏期损失程度都随着Fe2+浓度的增加而增加。高浓度Fe2+瞬间刺激溶酶体脂质过氧化，并在10 min内达到最高水平；而随后的最大延迟损失在20分钟内实现。在Fe3+-ADP +抗坏血酸或Fe2+系统中，维生素A或维生素E的存在都能有效地阻止MDA的形成和延迟的损失。
Peroxidative degradation of the lysosomal membrane and the resultant release of hydrolytic enzymes may be responsible for hepatocellular injury in Fe toxicity. Highly purified hepatic lysosomes were exposed to Fe salts in vitro; the nature of this Fe-mediated process of injury and the susceptibility of the lysosomal integrity were studied. Native hepatic lysosomes from rats were isolated by free flow electrophoresis. Incubation of the lysosomes at 37.degree. C with Fe3+-ADP in the presence of ascorbate resulted in rapid generation of malondialdehyde [MDA], which approached a plateau at 20 min. The loss of lysosomal latency, determined as an increased percentage free activity of N-acetyl-.beta.-glucosaminidase, also occurred and reached a maximum loss at 30 min. The half-maximal level of ascorbate, required to promote the Fe3+-ADP mediated lysosomal peroxidation, was .apprx. 10 .mu.M; high concentrations of ascorbate were inhibitory and half-maximal inhibition was achieved at a concentration of 2 mM. The Fe-mediated lysosomal peroxidation was not inhibited by most active O2 scavengers and appeared to depend solely on the generation of Fe2+ species. When a fresh solution of Fe2+ was incubated with the lysosomes, both the extent of lipid peroxidation and the degree of latency loss increased as a function of increasing Fe2+ concentration. High concentrations of Fe2+ stimulated lysosomal lipid peroxidation instantaneously and reached the highest level within 10 min; whereas the subsequent maximum loss of latency was achieved within 20 min. Both the MDA formation and the loss of latency in either the Fe3+-ADP + ascorbate or the Fe2+ system were effectively prevented by the presence of vitamin A or vitamin E.