Study on Oxidative Adaptive Response and Cell Death Pathway in Mouse Hippocampus Neurons (HT-22) Induced by Copper Ion

• Main Authors: Yang, Sheng-Jyun, 楊盛鈞
• Other Authors: Hwang, Deng-Fwu
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/5scg4b

碩士 === 國立臺灣海洋大學 === 食品科學系 === 107 === Copper (Cu) is one kind of the most rich metal in the earth. There are also many applications in industry. Copper is a cofactor for many enzymes involving in hematopoietic function in human body. Proper copper intake is important for physiological functions. However, copper is also a harmful environmental pollutant, mainly from industrial pollution such as electroplating, smelting, scrap metal processing and algaecide for aquaculture. The most famous case affected by copper pollution is the "green oysters" in the west coast of Taiwan, and copper pollution in water can affect the farming. The toxicity mechanism of copper is related to oxidative stress. Cu2+ can induce the formation of large amounts of reactive oxygen species (ROS) or be the catalyst of oxidation, which can interfere with the normal operation of cells, imbalance of antioxidant system, cell damage, abnormal enzyme activity, DNA cleavage and even induction of apoptosis. Copper ion is mainly harmful to the liver and kidneys and is also indicated to be associated with Alzheimer's disease, but the detailed mechanism is still unknown. Therefore, this study will use Alzheimer's disease-related mouse hippocampal neurons (HT-22) to investigate the oxidative stress and toxicological mechanism of copper ion on brain. The chapter 1 of this study intends to investigate the cytotoxicity and oxidative stress induced by copper ion. With the increase of copper ion concentration, the cell survival rate decreased steadily. The release amount of lactate dehydrogenase (LDH) also increased significantly. The cells were also gradually atrophied, broken or even suspended. In terms of oxidative stress, ROS also increases and total thiol content decreases respectively. The antioxidant enzyme superoxide dismutase (SOD) activity shows a trend of increasing first and then decreasing. In summary, copper ion induces a large increase in ROS with neurons, resulting the induction of intracellular substance oxidation, the inhibition of antioxidant system and cells death. Basing on the results above, the chapter 2 of this study investigates the mitochondrial dysfunction and cell death pathway induced by copper ion. Intracellular calcium concentration and mitochondrial membrane potential (MMP), which regulate apoptosis, are significantly increased and decreased respectively, indicating an increase in endoplasmic reticulum stress (ER stress) and further affecting the dissipation of MMP. Because MMP is related to cellular respiration, its strength can affect energy production, so ATP production also decreases significantly. In term of the cell death pathway, the proportion of apoptotic cells is higher than necrotic cells and the cysteine dependent aspartate-specific protease-3/7 (Caspase-3/7) activity was also increased significantly, indicating that copper ion can induce apoptosis by mitochondrial pathway and necrosis at high concentrations in the neurons.