Caspase-3-Independent Internucleosomal DNA Fragmentation in Ischemic Acute Kidney Injury
Caspase-3-Independent Internucleosomal DNA Fragmentation in Ischemic Acute Kidney Injury
复制标题
DOI：
10.1159/000337358
复制
发表时间：
2012-06
影响因子：
--
通讯作者：
Taiko Yoshida;A. Shimizu;Y. Masuda;A. Mii;E. Fujita;Kaoru Yoshizaki;S. Higo;G. Kanzaki;Y. Kajimoto;H. Takano;Y. Fukuda
中科院分区：
文献类型：
--
作者：
Taiko Yoshida;A. Shimizu;Y. Masuda;A. Mii;E. Fujita;Kaoru Yoshizaki;S. Higo;G. Kanzaki;Y. Kajimoto;H. Takano;Y. Fukuda
背景/目的：缺血再灌注中的肾小管细胞死亡并不遵循经典的细胞凋亡或坏死表型。我们描述了缺血性急性肾损伤（AKI）中受损肾小管上皮细胞的形态和生化特征。方法：通过 60 分钟缺血，然后再灌注 24 小时，诱导大鼠发生缺血性 AKI。在死亡过程中检查光镜和电子显微镜 TUNEL（LM-TUNEL 和 EM-TUNEL）、提取的 DNA 的凝胶电泳以及 caspase-3 的参与情况。结果：再灌注后 12 小时和 18 小时，受损的肾小管上皮细胞具有浓缩和 LM-TUNEL 阳性 (+) 细胞核，在凝胶电泳上显示 DNA“阶梯”图案。 EM-TUNEL+细胞的特征是细胞核具有浓缩和聚集的染色质，而细胞质则显示出不可逆的坏死。再灌注后肾脏中 caspase-3 的蛋白水平和活性没有增加。此外，半胱天冬酶抑制剂 (ZVAD-fmk) 未能抑制 DNA 断裂并防止缺血性 AKI 中的肾小管上皮细胞死亡。结论：缺血性 AKI 中发生不可逆性坏死的受损肾小管上皮细胞中发生不依赖于 Caspase-3 的核小体间 DNA 断裂。这种细胞死亡的方式可能与称为细胞凋亡性坏死、坏死或坏死性凋亡的细胞死亡相同。缺血再灌注损伤激活不依赖 caspase-3 的核酸内切酶，进而诱导肾小管上皮细胞不可逆损伤，并可能导致 AKI 的发生和发展。
Background/Aims: Renal tubular cell death in ischemia-reperfusion does not follow the classical apoptosis or necrosis phenotype. We characterized the morphological and biochemical features of injured tubular epithelial cells in ischemic acute kidney injury (AKI). Methods: Ischemic AKI was induced in rats by 60 min of ischemia followed by 24 h of reperfusion. Light and electron microscopic TUNEL (LM-TUNEL and EM-TUNEL), gel electrophoresis of extracted DNA, and caspase-3 involvement were examined during the development of death. Results: Damaged tubular epithelial cells with condensed and LM-TUNEL-positive (+) nuclei were prominent at 12 and 18 h after reperfusion with DNA ‘ladder’ pattern on gel electrophoresis. EM-TUNEL+ cells were characterized by nuclei with condensed and clumping chromatin, whereas the cytoplasm showed irreversible necrosis. The protein levels and activity of caspase-3 did not increase in kidneys after reperfusion. In addition, caspase inhibitor (ZVAD-fmk) failed to inhibit DNA fragmentation and prevent tubular epithelial cell death in ischemic AKI. Conclusion: Caspase-3-independent internucleosomal DNA fragmentation occurs in injured tubular epithelial cells undergoing irreversible necrosis in ischemic AKI. The manner of this cell death may be identical to the cell death termed apoptotic necrosis, aponecrosis, or necrapoptosis. Ischemia-reperfusion injury activates caspase-3-independent endonuclease, which in turn induces irreversible damage of tubular epithelial cells, and may contribute to the initiation and development of AKI.