壳寡糖对神经细胞的抗氧化保护作用研究

摘要

Oxidative damage of nerve cells is one of the most important causes leading to neurodegenerative diseases including Alzheimer's disease (AD).To investigate the protection mechanism of chitosan oligosaccharide (COS) on nerve cells,hydrogen peroxide was employed as a source of oxidative stress to set up an injury model for SH-SY5Y cells.MTT assay,cellular MDA level and LDH releases,Hoechst 33342 fluorescence staining and flow cytometry were conducted to examine the cellular apoptosis.Then,Western-blot was carried out to analyze the expression of apoptosis-related proteins and further investigate the effect of COS against hydrogen peroxide-induced oxidation.The results showed that COS could effectively improve the cellular survival rate,inhibit LDH releases and repress MDA increase under hydrogen peroxide stress.Besides,COS exhibited repressive effect against hydrogen peroxide-mediated apoptosis,and decreased the ratio of Bax/Bcl-2.These results suggest that the neuroprotective mechanism of COS on relieving oxidative stress induced by hydrogen peroxide may be related to its antioxidative effect,alleviation of lipid peroxidation damage and inhibition of cell apoptosis.%神经细胞发生氧化损伤是导致阿尔茨海默病等神经退行性疾病的重要原因之一.为探讨壳寡糖(chitosan oligosaccharide,COS)对神经细胞的保护机制,首先采用过氧化氢(hydrogen peroxide,H2O2)建立SH-SY5Y神经细胞氧化损伤模型,随后通过细胞存活率(MTT法)、丙二醛(MDA)含量、乳酸脱氢酶(LDH)释放量、Hoechst33342荧光染色法、流式细胞术研究各组细胞凋亡情况,并用Western-blot检测相关蛋白质的表达水平,从而分析COS对H202所致神经细胞氧化损伤的影响.研究发现,H2O2能明显诱导SH-SY5Y细胞损伤,而COS可抑制H2O2引起的细胞死亡,表现为神经细胞存活率升高、LDH释放量及MDA含量下降;且对H2O2所致细胞凋亡具有明显的抑制作用,凋亡蛋白Bax和抗凋亡蛋白Bcl-2的比值下降.上述结果提示COS保护机制可能与其抗氧化、减轻脂质过氧化损伤以及抑制细胞凋亡有关.