Papadopoulos M C, Koumenis I L, Yuan T Y, Giffard R G
Department of Anesthesia, Stanford University School of Medicine, CA 94305, USA.
Neuroscience. 1998 Feb;82(3):915-25. doi: 10.1016/s0306-4522(97)00320-5.
This paper investigates the vulnerability of astrocytes to oxidative injury as a function of age in culture in mice. Primary murine cortical astrocyte cultures of different ages were exposed to H2O2, combined oxygen-glucose deprivation or glucose deprivation. Astrocytes became more vulnerable to damage from each injury paradigm with age, showing transitions between 15 and 22 days. Both the antioxidant glutathione and superoxide dismutase activity increased after 30 days in culture, while catalase activity did not change up to 34 days. When the decrease in glutathione with injury was measured, young cells showed no change with H2O2 and decreases of < 20% after oxygen-glucose deprivation or glucose deprivation, while older cultures lost > 50% of their glutathione with the same insults. Since iron can be a catalyst for hydroxyl radical formation, we stained cultures and found both iron staining and ferritin immunoreactivity increased with age. Increased iron correlated with protection by deferoxamine against H2O2 injury. The three injury paradigms each had a unique pattern of protection by antioxidants. Dimethylthiourea, a hydrophilic antioxidant, protected from all three insults. Trolox, a lipophilic antioxidant, protected older astrocytes from oxygen-glucose deprivation and glucose deprivation. Deferoxamine provided near complete protection from H2O2, partial protection from oxygen-glucose deprivation and no protection from glucose deprivation. As evidence of increasing oxidative stress, lipid peroxidation resulting from oxygen-glucose deprivation increased with age, assessed with cis-parinaric acid. The increasing sensitivity of ageing astrocytes to oxidative injury occurs while antioxidant defenses are maintained. Increased sensitivity to H2O2 or oxygen-glucose deprivation correlates with iron accumulation.
本文研究了小鼠培养物中星形胶质细胞对氧化损伤的易感性与年龄的关系。将不同年龄的原代小鼠皮质星形胶质细胞培养物暴露于过氧化氢、联合氧糖剥夺或糖剥夺环境中。随着年龄的增长，星形胶质细胞对每种损伤模式的损伤变得更加敏感，在15至22天之间出现转变。培养30天后，抗氧化剂谷胱甘肽和超氧化物歧化酶活性均增加，而过氧化氢酶活性在34天之前没有变化。当测量损伤时谷胱甘肽的减少时，年轻细胞在过氧化氢处理后没有变化，在氧糖剥夺或糖剥夺后减少<20%，而较老的培养物在相同损伤下失去了>50%的谷胱甘肽。由于铁可以催化羟基自由基的形成，我们对培养物进行染色，发现铁染色和铁蛋白免疫反应性均随年龄增加。铁的增加与去铁胺对过氧化氢损伤的保护作用相关。三种损伤模式各自具有独特的抗氧化剂保护模式。亲水性抗氧化剂二甲基硫脲对所有三种损伤均有保护作用。亲脂性抗氧化剂生育三烯酚保护较老的星形胶质细胞免受氧糖剥夺和糖剥夺。去铁胺对过氧化氢提供近乎完全的保护，对氧糖剥夺提供部分保护，对糖剥夺没有保护作用。作为氧化应激增加的证据，用顺式-十八碳四烯酸评估，氧糖剥夺导致的脂质过氧化随年龄增加。衰老的星形胶质细胞对氧化损伤的敏感性增加发生在抗氧化防御维持的同时。对过氧化氢或氧糖剥夺的敏感性增加与铁积累相关。
