摘要目的:探讨肿瘤坏死因子α（TNF-α）是否通过调控超快速延迟整流钾电流（ Ikur）参与心房肌细胞的电重塑，以及Src激酶是否参与其中。 方法:将大鼠胚胎心肌细胞株H9c2细胞置于DMEM培养基中，将小鼠心房肌细胞株HL-1细胞置于Claycomb培养基中，于37 ℃ 5% CO 2培养箱中培养。以正常培养的细胞为对照组。予以不同浓度TNF-α干预细胞24 h，分别为TNF-α 25 ng/ml组、TNF-α 50 ng/ml组和TNF-α 100 ng/ml组。为观察Src抑制剂PP1能否逆转TNF-α作用，设置PP1+TNF-α组：先予10 μmol/L的PP1预处理1 h后再加入100 ng/ml TNF-α干预细胞24 h。采用Western blot检测各组细胞中形成 Ikur的主要钾通道蛋白Kv1.5、Src的表达水平。采用全细胞膜片钳检测各组细胞的 Ikur密度。 结果:（1）H9c2细胞中，TNF-α 100 ng/ml组细胞的Kv1.5蛋白表达水平低于对照组及TNF-α 25 ng/ml组（ P均<0.05）。各组细胞间Src蛋白表达水平差异无统计学意义（ P>0.05），但TNF-α 25 ng/ml组、TNF-α 50 ng/ml组及TNF-α 100 ng/ml组细胞磷酸化Src（p-Src）蛋白表达水平均高于对照组（ P均<0.05）。TNF-α 50 ng/ml组及TNF-α 100 ng/ml组细胞 Ikur电流密度均小于对照组（ P均<0.05）。PP1+TNF-α组细胞Kv1.5蛋白表达水平高于TNF-α 100 ng/ml组（ P<0.05）， Ikur电流密度大于TNF-α 100 ng/ml组（ P<0.01）。PP1+TNF-α组细胞Kv1.5蛋白表达水平及 Ikur电流密度与对照组比较差异均无统计学意义（ P均>0.05）。（2）在心房肌细胞株HL-1细胞中，TNF-α 100 ng/ml组细胞Kv1.5蛋白表达水平低于对照组和TNF-α 25 ng/ml组（ P均<0.01）。TNF-α 100 ng/ml组细胞p-Src蛋白表达水平高于对照组（ P<0.05）。各组细胞Src蛋白表达水平差异无统计学意义（ P>0.05）。PP1+TNF-α组细胞Kv1.5蛋白表达水平高于TNF-α 100 ng/ml组（ P<0.05）。 结论:在心房肌细胞中，TNF-α可能通过激活Src激酶降低Kv1.5蛋白表达水平，进而下调 Ikur，参与心房颤动的发生及发展过程。

abstractsObjective:To investigate whether inflammatory factor tumor necrosis factor-α (TNF-α) is involved in the electrical remodeling of cardiomyocytes by regulating ultra-rapid delayed rectifier K + current ( Ikur) and the role of Src kinase. Methods:H9c2 cells, embryonic cardiomyocytes of rat, were cultured in Dulbecco′s modified Eagle′s medium (DMEM) and atrium-derived HL-1 cells were cultured in Claycomb medium. Both H9c2 and HL-1 cells were cultured at 37 ℃ with 5% CO 2. Cells cultured in normal conditions without additional treatment served as control group. Experimental groups were treated with different concentration of TNF-α (25 or 50 or 100 ng/ml) for 24 hours. To study whether Src specific inhibitor PP1 could abrogate the effect of TNF-α, cells were pre-treated with 10 μmol/L PP1 for 1 hour, followed by TNF-α (100 ng/ml) for 24 hours. Western blot and the whole cell patch clamp technique were used to detect the protein expression of Kv1.5 and Src and Ikur in each group. Results:(1) In H9c2 cells, high concentration of TNF-α treatment (100 ng/ml) significantly reduced the Kv1.5 protein expression compared with control group and TNF-α 25 ng/ml group (both P<0.05). Compared with control group, the expression of p-Src protein was higher in 25 ng/ml, 50 ng/ml, 100 ng/ml TNF-α group (all P<0.05), but there was no statistical difference in the expression of Src protein among groups ( P>0.05). In addition, the current density of Ikur was decreased in 50 ng/ml, 100 ng/ml TNF-α group (both P<0.05). Furthermore, the expression of Kv1.5 protein and the current density of Ikur were increased in PP1+TNF-α group compared with TNF-α 100 ng/ml group (both P<0.05). There was no statistical difference in the expression of Kv1.5 protein and the current density of Ikur between the control group and PP1+TNF-α group (both P>0.05). (2) In atrium-derived HL-1 cells, the expression of Kv1.5 protein was reduced in 100 ng/ml TNF-α group compared with control group and TNF-α 25 ng/ml group (both P<0.01). In addition, the expression of p-Src protein was increased in TNF-α 100 ng/ml group compared with control group ( P<0.05), but there was no statistical difference in the protein expression of Src among groups ( P>0.05). The expression of Kv1.5 protein was increased in PP1+TNF-α group compared with TNF-α 100 ng/ml group ( P<0.05). Conclusion:TNF-α is involved in the pathogenesis of atrial fibrillation, probably via decreasing Ikur current density in atrium-derived myocytes through the activation of Src kinase.