NEW METHODOLOGY FOR EVALUATION OF RENAL DAMAGE CAUSED BY HEAVY METALS ON THE TUBULAR LEVEL

由镉和汞等重金属引起的肾损伤的特征在于近端肾小管功能障碍。然而，我们已经发现，金属硫蛋白，其蛋白质可以诱导这些金属和解毒这些金属是目前更丰富的肾单位的远端部分。使用一种新的同步辐射X射线荧光分析，具有足够的分辨率，以定位特定细胞中的金属，我们可以确定肾组织切片中的重金属定位。我们还建立了原位杂交金属硫蛋白mRNA地高辛标记的核糖探针。然后，我们研究了镉和汞处理的大鼠肾脏标本中重金属和金属硫蛋白及其mRNA的分布之间的关系。通过原位杂交和免疫组化方法，我们发现金属硫蛋白及其mRNA在近端和远端肾小管细胞中以不同的方式定位，这表明使用这两种方法可用于鉴定特定蛋白质合成和/或转运发生的特定细胞。

Renal damage that is caused by heavy metals like cadmium and mercury has been characterized by proximal tubular dysfunction. However, we have found that metallothionein, the protein of which can be inducible by these metals and detoxify these metals is present more abundant in distal portions of nephrons. Using a novel synchrotron radiation X-ray fluorescence analysis with sufficient resolution to locate metals in specific cells, we could determine heavy metal localization in renal tissue sections. We also established in situ hybridization of metallothionein mRNA using digoxigenin-labeled riboprobe. Then, we have studied relationships between distributions of heavy metals, metallothionein and its mRNA in cadmium and mercury treated rat kidney specimens. By using in situ hybridization and immunohistochemisry of metallothionein, we have found that metallothionein and its mRNA localize in different manners in proximal and distal tubular cells, suggesting that the use of these two methods is useful in identifying the specific cells where synthesis and/or transport of a particular protein occurs.