The role of singlet oxygen in ischemia-reperfusin injury : the study using laser scanning confocal microscopy and electron paramagnetic resinance

为了阐明单线态氧在缺血再灌注损伤中的作用，我们进行了以下研究。1)对单线态氧的生成和猝灭进行了化学检测。当含有6-甲酰基pterin （6FP）的溶液被荧光照射时，产生单线态氧，并被n -乙酰半胱氨酸（NAC）、谷胱甘肽（GSH）和组氨酸猝灭。2)利用大鼠肝细胞检测光化学生成的单线态氧的生物学效应。将6FP注入肝细胞后，用荧光光照可诱导肝细胞死亡，NAC和GSH预处理可减轻肝细胞死亡，组氨酸则不能。3)检测6FP产生的活性氧（ROS）对药物性细胞损伤的影响。当大鼠肝细胞负荷肿瘤坏死因子-α和放线菌素D时，可诱导凋亡细胞损伤，6FP预处理可减轻凋亡细胞损伤。6FP产生的ROS可以抑制caspase活性，减轻凋亡细胞损伤。4)利用人胰腺癌细胞系Panc-1细胞，研究了一种新型蝶呤衍生物的光动力学效应。将新型翼虫素注入细胞后，用紫外线（UV-A）照射可诱导细胞死亡。辐照过程中产生的单线态氧被认为是导致细胞死亡的原因。5)以人白血病细胞系U937细胞为实验对象，研究6FP对热诱导细胞凋亡的影响。6FP负载细胞，44℃热休克20 min后，凋亡细胞死亡增强。6FP产生的过氧化氢被认为是增强的原因。6)检测脂多糖（LPS）诱导的ROS生成和谷胱甘肽水平的变化及其与树突状细胞成熟的关系。结果表明，活性氧参与了细胞因子的产生。

To elucidate the role of singlet oxygen in ischemia-reperfusion injury, the following studies were performed.1)The generation and quenching of singlet oxygen were chemically examined. When the solution including 6-formylpterin (6FP) was irradiated by fluorescent llight, singlet oxygen was generated, which was quenched by N-acetyl-L-cystein (NAC), glutathine (GSH) and histidine.2)The biological effects of photochemically generated singlet oxygen against were examined using rat hepatocytes. When the hepatocyted were loaded with 6FP and then irradiated by fluorescent llight, the cell death was induced, which was attenuated by the pre-treatment with NAC and GSH, but not with histidine.3)The effects of reactive oxygen species (ROS) generated by 6FP on the drug-induced cell injury were examined. When the rat hepatocytes were loaded with tumor necrosis factor-α and actinomycin D, the apoptotic cell injury was induced, which was attenuated by the pre-treatment with 6FP. The generated ROS by 6FP was thought to suppress the caspase activity and attenuated the apoptotic cell injury.4)The photodynamic effects of a novel pterin derivative were examined using a human pancreatic cancer cell line, Panc-1 cells. When the cells were loaded with the novel pterin and irradiated by ultraviolet (UV-A), the cell death was induced. The singlet oxygen generated during irradiation was thought to cause the cell death.5)The effects of 6FP on the heat-induced apoptosis were examined using a human leukemia cell line, U937 cells. When the cells were loaded with 6FP and exposed to heat shock (44℃ for 20 min), the apoptotic cell death was enhanced. The hydrogen peroxide generated by 6FP was thought to cause the enhancement.6)Lipopolysaccharide (LPS)-induced ROS generation and changes in glutathione level and their relation to the maturation of dendritic cells were examined. It was revealed that the ROS was involved in the cytokine production.