Rauen U, Polzar B, Stephan H, Mannherz H G, de Groot H
Institut für Physiologische Chemie, Universitätsklinikum, D-45122 Essen, Germany.
FASEB J. 1999 Jan;13(1):155-68. doi: 10.1096/fasebj.13.1.155.
When cultured hepatocytes were incubated in cell culture medium at 4 degreesC for up to 30 h and then returned to 37 degreesC, blebbing of the plasma membrane, cell detachment, chromatin condensation and margination, enhanced nuclear stainability with Hoechst 33342, ruffling of the nuclear membrane, and DNA fragmentation occurred. Similar to hepatocytes, cultured liver endothelial cells exhibited blebbing, chromatin condensation and margination, marked nuclear condensation, and increased stainability with Hoechst 33342 when exposed to hypothermia/rewarming. In both cell types, the occurrence and extent of these alterations were dependent on the duration of the cold incubation period. This cold-induced apoptosis was inhibited by hypoxia, by an array of free radical scavengers/antioxidants, and by iron chelators. However, the extent of the protection by the different antioxidants was different in the two cell types: iron chelators provided complete protection in liver endothelial cells but only partial protection in hepatocytes, whereas lipophilic antioxidants such as alpha-tocopherol provided complete protection in both cell types. During cold incubation, and especially during rewarming, lipid peroxidation occurred. These results suggest that the formation of reactive oxygen species (ROS) is a key mediator of cold-induced apoptosis, with ROS formation being completely iron-mediated in liver endothelial cells and partially iron-mediated in hepatocytes.
当培养的肝细胞在4℃的细胞培养基中孵育长达30小时，然后再回到37℃时，会出现质膜起泡、细胞脱离、染色质凝聚和边缘化、用Hoechst 33342染色时核染色增强、核膜起皱以及DNA片段化。与肝细胞相似，培养的肝内皮细胞在经历低温/复温时也表现出起泡、染色质凝聚和边缘化、明显的核凝聚以及用Hoechst 33342染色时染色性增加。在这两种细胞类型中，这些改变的发生和程度取决于冷孵育期的持续时间。这种冷诱导的细胞凋亡受到缺氧、一系列自由基清除剂/抗氧化剂以及铁螯合剂的抑制。然而，不同抗氧化剂的保护程度在两种细胞类型中有所不同：铁螯合剂在肝内皮细胞中提供完全保护，但在肝细胞中仅提供部分保护，而亲脂性抗氧化剂如α-生育酚在两种细胞类型中都提供完全保护。在冷孵育期间，尤其是在复温期间，发生了脂质过氧化。这些结果表明，活性氧（ROS）的形成是冷诱导细胞凋亡的关键介质，ROS的形成在肝内皮细胞中完全由铁介导，而在肝细胞中部分由铁介导。
