黄连素对缺氧复氧诱导大鼠心肌细胞内Nrf2/Keap1的影响

目的　探讨黄连素(BR)对大鼠H9c2心肌细胞缺氧/复氧(H/R)损伤后凋亡的影响及其作用机制。 方法　将培养的H9c2心肌细胞随机分为：正常对照组(NC组)、单纯药物组(BR组)、缺氧/复氧组(H/R组)、药物低剂量LBR组(1.5×10-6 mol/L)及高剂量HBR组(1.5×10-4 mol/L)。处理结束后，用MTT比色法检测H9c2心肌细胞的活力，用Hoechst33258染色检测细胞核形态的变化，用Western blot法检测Nrf2, Keap1蛋白的表达。 结果　与NC组比较，单纯BR对H9c2心肌细胞无影响。与H/R组比较，低、高剂量BR组细胞的活力明显上升(65.2±1.6%; 82.3±1.4%) (P<0.01)，心肌细胞的凋亡率明显减少(P<0.05)，Western blot的结果显示，BR可明显促进抗氧化相关蛋白Nrf2表达，抑制Keap1的表达。 结论　 BR对H9c2心肌细胞H/R损伤后的凋亡具有显著的抑制作用，可能与其促进抗氧化核转录因子Nrf2表达有关。

Effects of berberine on the expression of Nrf2/Keap1 in hypoxia reoxygenation induced myocardial cells

Objective　To examine the effect of berberine on hypoxia reoxygenation induced apoptosis in myocardial cells and to explore the potential mechanisms involved.　Methods　H9C2 cardiac muscle cells were divided into: normal control group (NC group), simple berberine group (BR group), hypoxia reoxygenation group (HR group) and drug treatment group (divided into LBR group: 1.5×10-6 mol/L, HBR group 1.5×10-4 mol/L). Myocardial cell vitality was detected by MTT, nucleus morphological changes were examined using Hoechst 33258 dye and Nrf2 and Keap1 protein expressions were detected by Western blot.　Results　Compared with that in NC group, simple berberine exerted no effect on myocardial cells in BR group. Compared with those in HR group, the cell vitality in treatment groups increased((65.2±1.6)%; (82.3±1.4)%; P<0.01)，and apoptosis decreased significantly(P<0.05). Western blot results showed that berberine increased the expression of the antioxidant-related protein Nrf2, and reduced the level of Keap1. Conclusion　Berberine has significant protective effect on hypoxia reoxygenation induced apoptosis in myocardial cells possibly by enhancing the release of Nrf2 and decreasing the expression of Keap1.