水飞蓟宾抑制NF-κB活化下调H_2O_2诱导心肌细胞iNOS表达的实验研究

Down-regulates iNOS expression of silibinin by inactivation of NF-κB in H_2O_2-induced H9C2 cardiomyocytes

目的探讨水飞蓟宾(SIL)对H2O2诱导状态下H9C2心肌细胞iNOS的调节作用及其相关的分子机制。方法将大鼠心肌H9C2细胞分为对照组(Control组)、水飞蓟宾+H2O2组(SIL+H2O2组)和H2O2组三组。在200μM的H2O2干预6小时后使用RT-PCR法和western blot法对H9C2心肌细胞iNOS mRNA和蛋白的表达水平进行检测,使用western blot法对H9C2心肌细胞NF-κB磷酸化水平(Phospho-NF-κB p65/total NF-κB p65比值)进行测量。结果与对照组相比较,在H2O2干预6小时后H9C2心肌细胞iNOS mRNA和蛋白的表达水平和NF-κB p65活化水平均明显增高,差异均有统计学意义(P均<0.05);但与H2O2组相比较水飞蓟宾+H2O2组iNOS mRNA和蛋白的表达及NF-κB p65磷酸化水平的增加更加显著,差异均有统计学意义(P均<0.05)。结论在过氧化氢诱导的H9C2心肌细胞氧化应激和损伤过程中水飞蓟宾可能可以通过抑制NF-κB p65的活化下调iNOS的表达,对心肌细胞有保护作用。

Objective To investigate the role of silibinin （SIL） on the regulation of iNOS expression in H2O2-in- duced injury, and its potential mechanism in rat H9C2 cardiomyocytes. Methods H9C2 cardiomyocytes were divided into three groups, Control group, SIL＋H2O2 group and H2O2 group. After 6 hours H202 stimulation, RT-PCR was used to measure the mRNA expression of iNOS. Meanwhile, western blot was performed to analyze the protein expression of iN- OS and the ratio of phospho-NF-κB p65/total NF-κB p65. Results After 6 hours H2O2 stimulation, the mRNA and pro- tein expression of iNOS was significantly enhanced, and the ratio of phospho-NF-κB p65/total NF-κB p65 was largely in- creased. Moreover, H2O2-induced the up-regulation of iNOS and the enhanced level of NF-κB p65 were both inhibited by silibinin in rat H9C2 cardiomyocytes. Conclusions Silibinin down-regulates iNOS expression possibly via inactivation of NF-κB p65 in H9C2 cardiomyocytes after H2O2 stimulation.