多西环素对缺氧大鼠心肌细胞缝隙连接蛋白43表达的影响

目的探讨多西环素对缺氧大鼠H9c2心肌细胞缝隙连接蛋白43(connexin 43,Cx 43)表达的影响及其可能的机制。方法培养大鼠H9c2心肌细胞,用Western Blotting法检测缺氧6 h、12 h、24 h后Cx43总蛋白的表达量及基质金属酶抑制剂(多西环素)、PI3K抑制剂(LY294002)、ERK1/2抑制剂(U0126)干预缺氧H9c2心肌细胞后Cx43总蛋白的表达量改变。结果缺氧组较空白对照组Cx43总蛋白表达量明显降低,差异有统计学意义(P<0.01)。缺氧6 h时,多西环素和U0126干预组较缺氧组Cx43总蛋白表达量明显增高,差异有统计学意义(P<0.05);缺氧12 h时,U0126干预组Cx43总蛋白表达量仍较缺氧组增高,差异有统计学意义(P<0.05);缺氧24 h时,多西环素和U0126干预后Cx43总蛋白表达量与缺氧组比较,差异无统计学意义(P>0.0.05)。LY294002干预组Cx43总蛋白表达量在观察时间范围内均较缺氧组显著降低,差异有统计学意义(P<0.01)。结论在培养的大鼠H9c2心肌细胞中,多西环素通过抑制基质金属酶增加缺氧心肌细胞Cx43总蛋白表达量,该作用至少部分抑制由ERK1/2信号介导的传导通路。

Effect of doxycycline on connexin 43 protein expression of cardiomyoblast cells in anoxic rat

Objectives To investigate the effects and the possible mechanisms of doxycycline on the expression of eonnexin 43 （Cx43） in rat H9c2 cardiomyoblast cells under hypoxic conditions. Methods H9c2 cardiomyoblast cells were cultured with hypoxia treatment for 6 h, 12 h and 24 h. Expressions of Cx43 in cardiomyocytes were quantified by Western Blotting, as well as the changes intervened by matrix metalloproteinases （MMPs） inhibitor （doxycycline）, PI3K inhibitor （LY294002）, ERK1/2 inhibitor （U0126） under hypoxic conditions. Results Expression of Cx43 in hypoxia group was obviously lower than that in normal control group （P〈0.01）. Expressions of Cx43 in doxycycline group and U0126 group were obviously higher than that in hypoxia group after 6 h of hypoxia （P〈0.05）. Expression of Cx43 in U0126 group was still obviously higher than that in hypoxia group after 12 h （P〈0.05）. Expressions of Cx43 in doxycycline group and U0126 group had no significant differences with that in hypoxia group after 24 h （P〉0.05）. Expressions of Cx43 in LY294002 group were significantly lower than that in hypoxia group during the observation （P〈0.01）. Conclusions By inhibiting the activity of MMPs, doxycycline increased Cx43 protein expression in anoxic H9c2 cardiomyoblast cells, which indicates that this effect can partly inhibit ERK1/2 signaling pathway.