Effects of Methamphetamine on Mitochondrial Function and Cell Growth in Human Neuroblastoma SH-SY5Y Cells

• Main Authors: Chi-Wei Wu, 吳志瑋
• Other Authors: Hsin-Chen Lee
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/18088895861325086847

碩士 === 國立陽明大學 === 藥理學研究所 === 93 === In Taiwan, methamphetamine (METH) is a wildly abused drug, which was originally used as a psychostimulant. Several studies have demonstrated that METH would cause neurotoxicity and damage neuronal cells in rat brain. In addition, METH would lead to neurodegeneration and cause a loss of neuronal function. Up to now, the cellular and molecular mechanisms of METH-induced damage still remain unclear, but the generally-accepted concept is that reactive oxygen species (ROS) play an important role in the process of METH-induced neurodegeneration. Mitochondria are the major source of energy in cells and they produce ATP to maintain normal cellular function through oxidative phosphorylation. Moreover, mitochondria are also the major source of ROS in cells and they are the major targets of ROS. On the other hand, mitochondria are also critical in the process of apoptosis (programmed cell death). According to the role of mitochondria in cell survival, the aim of this thesis is to study the effects of METH on mitochondria and cell growth in human neuroblastoma, SH-SY5Y cells. First, after treatment of the cells with 25~250 μg/ml METH, it was found that the viability of SH-SY5Y was decreased in a time- and dose-dependent manner. Secondly, 250 μg/ml METH caused a decrease in the protein level of cyclin D and also inhibited the phosphorylation of retinoblastoma (Rb), which then led to the cell cycle arrest at G0/G1 phase. After a 48 hr treatment of METH, apoptosis was found in 20% of total cell population. Thirdly, after exposure of METH to SH-SY5Y, it was found that mitochondrial membrane potential was decreased, but mitochondrial mass was increased. It was found that mitochondrial DNA (mt DNA) copy number was decreased. In addition, the mtDNA-encoded protein COX I and COX II were decreased after METH treatment. Moverover, METH treatment led to an increase of intracellular O2 consumption rate suggesting that the rate of electron transport in mitochondrial respiratory chain was elevated. It was also found that intracellular H2O2 production was increased after exposure of METH. Interestingly, pretreatment of coenzyme Q10 could attenuate the neurotoxicity induced by METH, which emphasized the importance of mitochondria in METH-induced neurotoxic process. In conclusion, these studies suggest that METH could result in the increase of intracellular reactive oxygen species (ROS) by impairing mitochondrial function. These effects may lead to more ROS production and causes neuronal cell death.