Bastyr University, 14500 Juanita Drive NE, Kenmore, WA 98028-4966, USA.
Dig Dis Sci. 2013 Jul;58(7):1899-908. doi: 10.1007/s10620-013-2648-3. Epub 2013 Apr 5.
Iron overload is associated with increased severity of nonalcoholic fatty liver disease (NAFLD) including progression to nonalcoholic steatohepatitis and hepatocellular carcinoma.
To identify potential role(s) of iron in NAFLD, we measured its effects on pathways of oxidative stress and insulin signaling in AML-12 mouse hepatocytes.
Rapid iron overload was induced with 50 μM ferric ammonium citrate and 8-hydroxyquinoline. Insulin response was measured by Western blot of phospho-protein kinase B. Lipid content was determined by staining with Oil Red O. Reactive oxygen species (ROS) were measured by flow cytometry using 5-(and 6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate. Oxidative stress was measured by Western blots for phospho-jnk and phospho-p38.
Iron increased ROS (p < 0.001) and oxidative stress (p < 0.001) and decreased insulin signaling by 33 % (p < 0.001). Treatment with stearic or oleic acids (200 μM) increased cellular lipid content and differentially modulated effects of iron. Stearic acid potentiated iron-induced ROS levels by two-fold (p < 0.05) and further decreased insulin response 59 % (p < 0.05) versus iron alone. In contrast, cells treated with oleic acid were protected against iron-mediated injury; ROS levels were decreased by half (p < 0.01) versus iron alone while insulin response was restored to control (untreated) levels. The anti-oxidant curcumin reduced effects of iron on insulin signaling, ROS, and oxidative stress (p < 0.01). Curcumin was similarly effective in cells treated with both stearic acid and iron.
An in vitro model of NAFLD progression is described in which iron-induced oxidative stress inhibits insulin signaling. Pathophysiological effects of iron were increased by saturated fat and decreased by curcumin.
铁过载与非酒精性脂肪性肝病（NAFLD）的严重程度增加有关，包括进展为非酒精性脂肪性肝炎和肝细胞癌。
为了确定铁在 NAFLD 中的潜在作用，我们测量了它对 AML-12 小鼠肝细胞中氧化应激和胰岛素信号通路的影响。
用 50μM 柠檬酸铁铵和 8-羟基喹啉快速诱导铁过载。通过 Western blot 测定磷酸化蛋白激酶 B 的胰岛素反应。用油红 O 染色测定脂质含量。通过 5-（和 6-）氯甲基-2'，7'-二氯二氢荧光素二乙酸酯的流式细胞术测定活性氧（ROS）。用 Western blot 测定磷酸化 JNK 和磷酸化 p38 来测定氧化应激。
铁增加了 ROS（p<0.001）和氧化应激（p<0.001），并使胰岛素信号降低了 33%（p<0.001）。用硬脂酸或油酸（200μM）处理增加了细胞内的脂质含量，并使铁的作用产生差异调节。硬脂酸使铁诱导的 ROS 水平增加了两倍（p<0.05），并使胰岛素反应进一步降低了 59%（p<0.05），而与铁单独处理相比。相比之下，用油酸处理的细胞对铁介导的损伤有保护作用；ROS 水平降低了一半（p<0.01），而胰岛素反应恢复到对照（未处理）水平。抗氧化剂姜黄素降低了铁对胰岛素信号、ROS 和氧化应激的作用（p<0.01）。姜黄素对用硬脂酸和铁处理的细胞同样有效。
描述了一个非酒精性脂肪性肝病进展的体外模型，其中铁诱导的氧化应激抑制了胰岛素信号。铁的病理生理作用被饱和脂肪增加，被姜黄素减少。
