叶黄素对高同型半胱氨酸血症大鼠氧化应激状态的影响及机制研究

Effect of lutein on oxidative stress of rats with high homocysteine and its relevent mechanism

目的揭示叶黄素（lutein）对高同型半胱氨酸血症（HHcy）大鼠氧化应激状态的影响及可能分子机制。方法以L-蛋氨酸灌胃构建Wistar大鼠HHcy模型并用lutein行干预处理。检测HHcy大鼠及lutein干预机体的氧化应激状态及调控抗氧化蛋白基因表达的转录激活因子Nrf2的基因表达改变。结果与对照组大鼠血清超氧化物歧化酶（SOD）活性（134.32±12.65） U/mL相比，HHcy模型大鼠血清SOD活性（95.63±10.92） U/mL显著降低（P〈0.05）。模型大鼠血清谷胱甘肽过氧化物酶（GPx）活性（121.66±18.64） U/mL较之对照组（183.17±21.29） U/mL亦显著降低（P〈0.05）。而lutein干预组大鼠血清SOD（126.75±11.26） U/mL及GPx 活力（167.18±19.66） U/mL均分别较模型组大鼠显著升高（P〈0.05）。与对照组大鼠血清MDA（丙二醛）浓度（5.11±0.68）μmol/L及羟自由基水平（0.53±0.05）U/L相比，HHcy模型大鼠血清MDA浓度（7.65±0.87）μmol/L及羟自由基水平（0.92±0.09） U/L显著升高（P〈0.05）。lutein干预组大鼠血清MDA浓度（6.44±0.91）μmol/L及羟自由基水平（0.74±0.06） U/L亦均较模型组大鼠显著降低（P〈0.05）。采用RT-PCR及Western blot检测显示，HHcy模型大鼠主动脉血管壁组织中SOD2及GPx1的mRNA及蛋白表达亦降低（P〈0.05）；而lutein干预组的SOD2及GPx1的mRNA水平及蛋白表达则明显上调，且调控抗氧化蛋白表达的转录因子Nrf2的基因表达亦显著上调（P〈0.05）。结论HHcy大鼠处于氧化应激的增强状态，lutein可显著干预抑制Hcy所介导的氧化应激亢奋，其机制可能是通过上调Nrf2的表达，进而诱导抗氧化蛋白的表达来介导的。

Objective To reveal the effect of lutein on the status of oxidative stress in rats with high homocysteine levels （HHcy） and relevent molecular mechanisms. Methods The wistar rat HHcy model was established by intra-gastric administration with L-methionine suspension and treated with lutein. The oxidative stress status and the gene expression changes of transcription Nf-E2-related factor2 （ Nrf2 ）, a regulation factor of down stream antioxidant protein gene expression, were detected in HHcy rats and lutein intervention rats. Results Compared with the rat serum SOD activities （ 134. 32 ± 12. 65 ） U/mL in the control group, the serum SOD activities in the HHcy model group （95.6 ± 10. 92） U/mL were significantly lower （P 〈 0. 05 ）. The serum glutathione peroxidase （GPx） activities in the HHcy model group （ 121.66 ± 18. 64） U/mL were also significantly lower as compared with the the control group （ 183. 17 ± 21.29） U/mL, P 〈 0.05. However, the serum SOD （126.75 ± 11.26） U/mL and GPx activities （167. 18 ± 19. 66） U/mL in the lutein intervention group were significantly higher as compared with the HHcy model group. As compared with the rat serum malondialdehyde （MDA） content （5. 11 ± 0. 68 ） μmol/L as well as the hydroxyl free radical levels （0. 53 ± 0. 05） U/L in the control group, the serum MDA content （7. 65 ± 0. 87 ） μmol/L and the hydroxyl free radical levels （0. 92 ± 0. 09） U/L in the HHcy model group were significantly higher. The serum MDA content （6.44 ± 0. 91 ） μmol/L and the hydroxyl free radical levels （0. 74 ± 0. 06） U/L in the lutein intervention group were significantly lower as compared with the HHcy model group. RT-PCR and Western blot results also showed decreased expression of SOD2 and GPxl mRNA in aorta epithelial tissues of HHcy model rats. With lutein intervention, the expressions of SOD2 and GPxlmRNA were significantly increased and the gene expression of Nrf2 also up-regnlated. Conclusions The Hhcy model rats were under the status of augmented oxidative stress, and carotenoid lutein could attenuate the Hcy-mediated oxidative stress, and its mechanism might be potentially associated with up-regulating the expression of Nrt2, thereby inducing the expression of its downstream antioxidant proteins.