Zalewski P D, Millard S H, Forbes I J, Kapaniris O, Slavotinek A, Betts W H, Ward A D, Lincoln S F, Mahadevan I
Department of Medicine, University of Adelaide, South Australia.
J Histochem Cytochem. 1994 Jul;42(7):877-84. doi: 10.1177/42.7.8014471.
We used an intracellular zinc-specific fluorophore, Zinquin, in conjunction with fluorescence video image analysis, to reveal labile zinc in pancreatic islet cells, which concentrate this metal for use in synthesis, storage, and secretion of insulin. Zinquin vividly demonstrated zinc in the islet cell secretory granules, which formed a brightly labeled crescent in the cytoplasm between one side of the nucleus and the plasma membrane. Lower but still appreciable amounts of zinc were detected in the remaining cytoplasm, but there was little labeling in the nucleus. Fluorescence intensity varied among islet cells, suggesting differences in zinc content. Their average fluorescence intensity greatly surpassed that of the surrounding pancreatic acinar cells in frozen sections of pancreas and in all other types of cell studied, including lymphocytes, neutrophils, fibroblasts, and erythrocytes. Less labile zinc was detected in cells of the mouse insulinoma cell line NIT-1, regardless of whether they were maintained in long-term culture in the presence or absence of exogenous extracellular zinc. Exposure of islet or insulinoma cells to a high concentration of glucose or other secretagogue decreased the content of labile zinc. Zinquin should be a useful probe for revealing changes in zinc homeostasis in islet B-cells that may be important in their dysfunction and death during diabetes.
我们使用一种细胞内锌特异性荧光团锌喹（Zinquin），结合荧光视频图像分析，来揭示胰岛细胞中的不稳定锌，胰岛细胞会积累这种金属以用于胰岛素的合成、储存和分泌。锌喹清晰地显示了胰岛细胞分泌颗粒中的锌，这些颗粒在细胞核一侧与质膜之间的细胞质中形成了一个明亮标记的月牙形。在其余细胞质中检测到较低但仍可观的锌含量，但细胞核中几乎没有标记。胰岛细胞之间的荧光强度有所不同，表明锌含量存在差异。在胰腺冰冻切片以及包括淋巴细胞、中性粒细胞、成纤维细胞和红细胞在内的所有其他研究类型的细胞中，它们的平均荧光强度大大超过了周围胰腺腺泡细胞。无论小鼠胰岛素瘤细胞系NIT-1的细胞是在有或没有外源细胞外锌的情况下长期培养，检测到的不稳定锌都较少。将胰岛或胰岛素瘤细胞暴露于高浓度葡萄糖或其他促分泌剂会降低不稳定锌的含量。锌喹应该是一种有用的探针，用于揭示胰岛B细胞中锌稳态的变化，这种变化在糖尿病期间其功能障碍和死亡过程中可能很重要。
