天津医药

• 实验研究 •    

糖尿病大鼠心肌硫氧还蛋白系统变化及其对Ito钾通道的影响

李学永   

  1. 解放军第251医院心内科
  • 收稿日期:2012-10-10 修回日期:2013-03-08 出版日期:2013-07-15 发布日期:2013-07-15
  • 通讯作者: 李学永

LI Xueyong   

  1. Department of Cardiology, 251th Hospital of PLA, Zhangjiakou 075000, China
  • Received:2012-10-10 Revised:2013-03-08 Published:2013-07-15 Online:2013-07-15
  • Contact: LI Xueyong

PDF (PC)

770

摘要：

【摘要】 目的   硏究糖尿病(DM)大鼠左室心肌细胞硫氧还蛋白()系统变化及其对瞬时外向钾电流(to)的影响。方法 45只SD大鼠分为DM组和对照组,DM组采用链尿佐菌素(STZ)诱导成模,2组大鼠行超声心动图(UCG)和心电图(ECG)检测左室舒张末期直径(LVEDD)和收缩末期直径(LVESD),短轴缩短率(LVFS)和射血分数(LVEF)及心率(HR)、QRS时限和校正QT(QTc)间期。取左室心肌组织样本,用紫外分光光度计测量Trx、谷氧还蛋白(Grx)、硫氧还蛋白还原酶(TrxR)、谷胱甘肽还原酶(GR),用5,5-二巯基双-2-硝基苯甲酸法测定左心室心肌自由巯基(P-SH)含量。用全细胞膜片钳方法记录大鼠心室肌Ito,用胰岛素(Ins)对DM大鼠心肌细胞进行体外孵育,并用TrxR抑制剂金诺芬(AF)和13-顺式视黄酸(RA)对DM+Ins组大鼠心肌细胞进行处理,观察Ins孵育、TrxR抑制剂处理前后Ito变化。结果 DM组HR、LVFS、LVEF、TrxR和GR低于对照组,LVEDD、LVESD、QRS时限、QTc间期、Trx、Grx和P-SH水平高于对照组;当刺激电压≥0mV时,DM+Ins组Ito密度均高于DM组;DM+Ins组Ito密度还高于Ins+RA组和Ins+AF组(均P<0.05)。结论 DM大鼠左室心肌细胞Trx系统功能下降,是导致心室功能降低和心律失常发生的电生理基础,而Ins能够逆转DM大鼠心肌细胞Ito下降。

关键词: 硫氧还蛋白质类, 硫氧还蛋白二硫化物还原酶, 谷氧还蛋白质类, 钾通道, 肌细胞, 心脏, 胰岛素, 糖尿病

Abstract: [Abstract]   Objective   To investigate the variation of the thioredoxin system (Trx)， and the role of it in transient outward potassium current (Ito) channels in left ventricular myocytes of diabetes mellitus (DM) in rats. Methods   Forty-five SD rats were divided into DM group and control group. DM group were treated with streptozotocin (STZ) to induce DM model.The values of left ventricular end diastolic diameter (LVEDD), end-systolic diameter (LVESD), fractional shortening (LVFS),ejection fraction (LVEF) and heart rate (HR), QRS duration and corrected QT (QTc) interval were detected by echocardiography (UCG) and electrocardiogram (ECG) in two groups. The left ventricular myocardial tissue samples were taken to detect the Trx,glutaredoxin (GRX)， thioredoxin reductase (TrxR) and glutathione reductase (GR) by using UV spectrophotometer.The level of free thiol (P-SH) of total cardiac protein was detected by 5, 5' -dithio-bis-2-nitrobenzoic acid method. Ito of the cardiomyocytes was recorded by whole-cell patch-clamp method. After being incubated in vitro with insulin（Ins）, treated with TrxR inhibitor-auranofin（AF) and 13-cis-retinoic acid（RA), the changes of Ito of the cardiomyocytes were observed.Results Compared with control group, the values of heart rate (HR), left ventricular minor axis decurtaion rate (LVFS), left ventricular ejection fraction (LVEF) and TrxR were lower in DM group. The values of LVEDD, LVESD, QRS and QTc intervals, Trx, Grx and P-SH were higher in DM group than those of control group. Ito density was significantly higher in DM+Ins group than that of DM group, Ins + RA group and Ins + AF group when the stimulation voltage ≥ 0 mV (P < 0.05).Conclusion   The impaired Trx system in diabetic rat myocardium was the electrophysiological basis of the reduced ventricular function and arrhythmia. And Ins was able to reversethe decreased Ito of cardiomyocytes in DM rats.

Key words: thioredoxins, thioredoxin-disulfide reductase, glutaredoxins, potassium channels, myocytes, cardiac, Insulin, 糖尿病