α-tocopherol inhibits oxidative stress induced by cholestanetriol and 25-hydroxycholesterol in porcine ovarian granulosa cells
α-tocopherol inhibits oxidative stress induced by cholestanetriol and 25-hydroxycholesterol in porcine ovarian granulosa cells
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DOI：
10.1023/a:1006967219894
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发表时间：
1999-04
影响因子：
4.3
通讯作者：
S. McCluskey;M. Hall;C. Stanton;R. Devery
中科院分区：
文献类型：
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作者：
S. McCluskey;M. Hall;C. Stanton;R. Devery
在原代培养的猪卵巢颗粒细胞中，研究了7-酮-胆固醇、α-环氧化物、胆固醇三醇和25-羟基胆固醇对细胞毒性的影响，以及α-生育酚对胆固醇和25-羟基胆固醇诱导的细胞毒性的保护作用。用台盼蓝染色法测定细胞存活率，用3-[4，5-二甲基噻唑-2-基]-2，5-二苯基四氮唑溴化法测定线粒体功能，发现2.5μM-α环氧化物、胆三醇和25-羟基胆固醇作用2 4h后，细胞线粒体功能明显下降。在相同培养条件下，7-酮胆固醇(2.5μM)对细胞存活率和线粒体功能无明显影响。2.5μM浓度的胆三醇作用24 h后，过氧化氢酶和超氧化物歧化酶这两种抗氧化剂防御酶的比活性显著升高(p<；0.001)，而25-羟基胆固醇处理的细胞仅超氧化物歧化酶活性显著升高(p<；0.01)。谷胱甘肽过氧化物酶的比活力与对照细胞相比没有变化。在暴露于7-酮胆固醇、α-环氧化物、胆三醇、25-羟基胆固醇和胆固醇后，硫代巴比妥酸活性物质的水平保持不变。在培养液中加入1μMα-生育酚显著提高了细胞存活率，并恢复了超氧化物歧化酶和过氧化氢酶的活性，以控制胆三醇处理的细胞和25-羟基胆固醇处理的细胞的超氧化物歧化酶活性。这些研究表明，颗粒细胞中生理浓度的胆烷三醇和25-羟基胆固醇的细胞毒性性质部分是由于氧化应激，但在α-生育酚的存在下，这种毒性可能会降低。
The cytotoxicity of oxysterols including 7-ketocholesterol, α-epoxide, cholestanetriol and 25-hydroxycholesterol and the possible protecting effect of α-tocopherol on cholestanetriol and 25-hydroxycholesterol-induced cytotoxicity were investigated in primary cultures of porcine ovarian granulosa cells. Cell viability as determined by % trypan blue staining and mitochondrial function as determined using 3-[4,5-dimethylthiazol-2-yl]-2,5- diphenyltetrazolium bromide (MTT) reduction were decreased significantly after 24 h exposure to 2.5 μM α-epoxide, cholestanetriol and 25-hydroxycholesterol. 7-ketocholesterol (2.5 μM) did not affect cell viability or mitochondrial function under the same culture conditions. The specific activities of catalase and superoxide dismutase, two antioxidant defense enzymes were increased significantly (p < 0.01) following 24 h exposure to 2.5 μM concentrations of cholestanetriol while only superoxide dismutase was increased in 25-hydroxycholesterol-treated cells (p < 0.001). Specific activity of glutathione peroxidase was unchanged relative to control cells. Levels of thiobarbituric acid reactive substances remained unchanged after exposure to 7-ketocholesterol, α-epoxide, cholestanetriol, 25-hydroxycholesterol and cholesterol. Administration of 1 μM α-tocopherol to the culture medium significantly improved cell viability and restored both superoxide dismutase and catalase activities to control levels in cholestanetriol -treated cells and only superoxide dismutase in 25-hydroxycholesterol-treated cells. These studies suggest that the cytotoxic nature of physiologically relevant concentrations of cholestanetriol and 25-hydroxycholesterol in granulosa cells is in part due to oxidative stress, but it may be reduced in the presence of a-tocopherol.