THE MECHANISM OF NEURO-2a CELL DEATH INDUCED BY H_2O_2
ZHANG Zhen YANG Wei ZHU Shan LU Zhi Gang ZHAI Zhong He (College of Life Science, Peking University, Beijing 100871)
Reactive oxygen species (ROS), such as H2O2, can be produced by enzymes involved in electron leakage of respiration chain in mitochondria, and by neurochemical enzymes such as monoamine oxidase in neural cells. ROS are toxic to cells, and can result in cell death. ROS also play an important role in some diseases, especially in neurodegenerative diseases by yet unknown mechanisms. In the current research, the N-2a neuroblastoma cell was treated with H2O2, and the morphological changes of cell death were characterized. Our results show that N-2a cell death is different from classical apoptosis, but belongs to type Ⅱ nerve cell programmed death, which shows condensed chromatin within intact nuclear envelope and no apoptolic body. The chromatin DNA of dead cells shows no internucleosomal cleavage, as well as no requirement for caspase-3, 1 activity. However, the H2O2-induced N-2a cell death can be inhibited by Bcl-XL. It can be concluded that type Ⅱ nerve cell death is the result of cell toxicity mediated by ROS. The results pave the way for further research of type Ⅱ nerve cell death.