糖尿病对大鼠左室心外膜细胞短暂外向钾电流的影响及分子基础  

The molecular mechanism of transient outward potassium currents decreasing in left ventricles from diabetic rats.

作　　者：邵阳贞[1] 张代民[1] 李勋[1] 蒋文平[1] 

机构地区：[1]苏州大学附属第一医院心内科,江苏苏州215006

出　　处：《中国心脏起搏与心电生理杂志》2008年第5期435-437,共3页Chinese Journal of Cardiac Pacing and Electrophysiology

摘　　要：目的研究大鼠左心室肌短暂外向钾电流(Ito)在糖尿病状态发生下降改变的分子机制。方法取体重150～200 g的雄性Sprague-Dawley大鼠,腹腔注射链脲菌素建立糖尿病大鼠模型,采用酶解法获得单个左室心外膜细胞,应用膜片钳全细胞方法记录Ito;用逆转录-聚合酶链式反应技术半定量编码该通道α亚单位mRNA的表达水平。结果与对照组相比,糖尿病大鼠左室心外膜细胞Ito密度显著降低,+60 mV时分别为27.38±1.16pA/pF(n=12)和16.85±2.31 pA/pF(n=25)(P<0.01);糖尿病大鼠左室心外膜肌细胞Ito通道α亚单位编码基因Kv4.2、Kv4.3 mRNA表达水平较对照组分别显著下调56.88%和46.57%;而Kv1.4 mRNA则较对照组上调约48.02%,三组基因表达水平的改变均具有显著性差异。结论糖尿病大鼠左心室肌外膜细胞Ito密度显著降低系编码该通道α亚单位的基因表达下调所致。Objective To investigate the molecular mechanism of transient outward potassium currents （Ito） decreasing in left ventricles from diabetic rats. Methods The diabetic model was established by injection of streptozoein peritoneally using male Spragne-Dawley rats weighing 150 -200 g. Single myoeytes of left ventricle epi were isolated by enzymatic perfusion. Ito was recorded with the whole-cell patch clamp teehnique, and then gene expressions of channel-forming sub- units were evaluated by the technique of reverse transeript-poly. Results The Ito density（ ＋ 60 mV）was significantly de- creased in diabetic rats compared with controls ± 27.38 ＋ 1.16 pA/pF（ n = 12） vs 16.85 ± 2.31 pA/pF（ n = 25 ） ,P 〈 0.01 ]. The gene expression levels of Kv4.2 and Kv4.3 encoding α-subunit of Ito in diabetic rats were markedly decreased in contrast with those of controls by 56.88% and 46.57% respectively, while the level of Kv1. 4 mRNA increased by 48.02% in diabet- ic group （ P 〈 0.01 ）. Conclusion The decreased density of Ito in left ventricle epi of diabetic rats is mainly attributed to the down regulation of gene expressions of channel-forming α-subunits. [ Chinese Journal of Cardiac Pacing and Electro- physiology,2008,22 （ 5 ） ：435 - 437 ]

关 键 词：电生理学 糖尿病 膜片钳 钾通道 心室肌细胞 

分 类 号：R331.38[医药卫生—人体生理学] R587.1[医药卫生—基础医学]