Hepatocyte necroptosis induced by ischemic acute kidney injury in rats

While ischemic acute kidney injury (IAKI) is known often to cause hepatic injury, little is known about necroptosis involved in the hepatic injury. The purposes of this study were to identify necroptosis involvement and observe morphological changes of hepatocytes in hepatic injury induced by IAKI in rats. Based on successfully established IAKI rat models, enzyme-linked immunosorbent assay illustrated a significant higher level of tumor necrosis factor a in serums of IAKI animals. Tumor necrosis factor receptor a (TNFRa) and receptor interacting protein kinase 3 (RIPk3) showed significant higher expressions in immunoblot analyses and positive hepatocytes of RIPk3 immunohistochemical staining were also evident in livers of IAKI rats. In addition, light microscopy revealed necrotic lesions that contain hepatocytes ongoing necroptosis besides necrotic cells in IAKI livers. Electron microscopy revealed at least three types of necrotic hepatocytes, they were edema necrosis, vacuolization necrosis, and necroptosis. Hepatocytes undergoing necroptosis had both necrosis and apoptosis morphological characteristics, they were necrosis cytoplasm and apoptosis-like nucleus. Among cellular organelles of hepatocyte with necrosis, membranous structures, such as cell membrane, endoplasmic reticular system, and mitochondria were more vulnerable to the stress of IAKI and deformed nucleuses varied in shape and lytic or pyknotic chromatin appearances were noted under insults of IAKI. In conclusion, hepatocyte undergoing necroptosis, RIPk3-mediated necroptosis partly contributes to hepatic necrosis induced by IAKI. Both membranous structures and nucleuses of hepatocyte were vulnerable to ischemic acute kidney injury.