Effects Of N-3Polyunsaturated Fatty Acids On Oxidative Stress-induced Toxicity And The Underlined Mechanisms

In this study, human neuroblastoma SH-SY5Y cell line was used as a model toinvestigate the effects of n-3polyunsaturated fatty acids on hydrogen peroxide-induced oxidative stress and cell toxicity. Cell survival and apoptosis rate werestudied by cell counting method and Hoechst staining. GSH levels, SOD activities,GSH-PX activities and ATP levels were assayed by testing kit. The expression ofUCP2and UCP4proteins was detected by RT-PCR technology.It was found that the cell survival rate decreased and the apoptosis rateincreased obviously when SH-SY5Y cells were treated with500μM H2O2. Asindicators of cell oxidative stress levels, GSH content, SOD enzyme activity had amarked reduction in cells, suggesting that the cells had a high oxidative stress. Theexpression of anti-apoptotic proteins Bcl-2was decreased while the expression ofpro-apoptotic proteins Bax was increased. As indicator of mitochondrial function,ATP production also decreased significantly, indicating that mitochondrial functionsuffered damages. The apoptosis phenomenon weakened and the cell survivalactivity increased after pretreatment with EPA and DHA, and downregulation ofBcl-2/Bax expression, suggesting that the oxidative stress induced by hydrogenperoxide and its effects on the toxicity obviously dropped. At the same time, theGSH content and SOD enzyme activity were significantly increased. In addition, thecontent of ATP also increased significantly. It can be seen that EPA and DHA cansignificantly reduce the oxidative stress level and improve the function ofmitochondrial metabolism. The expression of mitochondrial membrane transportprotein UCP2and UCP4still showed no obvious change.The conclusion is that n-3PUFA can inhibit hydrogen peroxide-inducedoxidative stress and cell toxicity by downregulating Bcl-2/Bax expression andincreasing GSH content, SOD enzyme activity and by improving mitochondrialfunction.