Olivari Francisco A, Hernández Pedro P, Allende Miguel L
Center for Genomics of the Cell, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
Brain Res. 2008 Dec 9;1244:1-12. doi: 10.1016/j.brainres.2008.09.050. Epub 2008 Sep 26.
Numerous physical and chemical agents can destroy mechanosensory hair cells in the inner ear of vertebrates, a process that is irreversible in mammals. Few experimental systems allow the observation of hair cell death mechanisms in vivo, in the intact animal, one of these being the lateral line system in the zebrafish. In this work we characterize the behavior of dying lateral line hair cells in fish exposed to low doses of copper in the water. The concentration of copper used in our study kills hair cells in a few hours, but removal of the metal is followed by robust regeneration of new hair cells. We use a combination of membrane and nuclear live stains, ultrastructural analysis and measurement of reactive oxygen species to characterize the events leading to the death of hair cells under these conditions. Our results show that a combination of necrotic cell death, accompanied by apoptotic features such as rapid DNA fragmentation, lead to the loss of these cells. We also show that hair cells exposed to copper undergo oxidative stress and that antioxidants can protect these cells from the effects of the metal. The study of this process in the zebrafish lateral line allows rapid morphological analysis of hair cell death and may be used as an efficient end point for molecule screens aimed at preventing these effects.
许多物理和化学因素能够破坏脊椎动物内耳中的机械感受毛细胞，这一过程在哺乳动物中是不可逆的。很少有实验系统能够在完整动物体内观察毛细胞的死亡机制，斑马鱼的侧线系统便是其中之一。在这项研究中，我们描述了暴露于水中低剂量铜的鱼类侧线毛细胞的死亡行为。我们研究中使用的铜浓度会在数小时内杀死毛细胞，但去除金属后，新的毛细胞会大量再生。我们结合使用膜和核活细胞染料、超微结构分析以及活性氧的测量，来描述在这些条件下导致毛细胞死亡的事件。我们的结果表明，坏死性细胞死亡与诸如快速DNA片段化等凋亡特征相结合，导致了这些细胞的丧失。我们还表明，暴露于铜的毛细胞会遭受氧化应激，抗氧化剂可以保护这些细胞免受金属的影响。对斑马鱼侧线中这一过程的研究能够快速进行毛细胞死亡的形态学分析，并且可作为旨在预防这些影响的分子筛选的有效终点。
