吡格列酮治疗β1肾上腺素能受体自身抗体诱导的大鼠室性心律失常的作用和电生理机制研究

Pioglitazone's Therapeutic Effect and Electrophysiological Mechanism on Rat Ventricular Arrhythmias Induced byβ1-adrenergic Receptor Autoantibodies

目的:探讨吡格列酮对β1肾上腺素能受体自身抗体(β1AAb)诱导的大鼠室性心律失常治疗作用及电生理机制。方法:将48只SD大鼠按随机数字表法等分为四组:对照组(佐剂注射)、β1AAb组[β1肾上腺素能受体细胞外第二环功能表位肽段(β1AR-ECLⅡ)配以佐剂背部多点注射进行主动免疫,2 mg/(kg·次)]、吡格列酮组[与β1AAb组同等主动免疫8周后,吡格列酮灌胃2周,4 mg/(kg·d)]、过氧化物酶体增殖物激活受体-γ特异性抑制剂GW9662组[与β1AAb组同等主动免疫8周后吡格列酮灌胃+GW9662腹腔注射2周,其中吡格列酮予以4 mg/(kg·d),GW9662予以1 mg/(kg·d)]。每2周Powerlab多通道生理仪记录心电图,取血。基线和第10周记录超声心动图,10周后进行心电生理、组织病理、免疫组化染色及电镜检查。结果:相较于对照组,β1AAb组室性心律失常诱发率较高、心室有效不应期(VERP)缩短、激动-恢复间期(ARI)延长;左心室射血分数(LVEF)和左心室短轴缩短率(LVFS)低;葡萄糖转运蛋白1(GLUT1)和肉碱棕榈酰转移酶1a(CPT1a)阳性染色面积占比较低;线粒体形态异常及网络损伤明显,P均<0.05。而吡格列酮组较β1AAb组,室性心律失常诱发率降低、VERP延长、ARI缩短;LVEF和LVFS恢复;GLUT1和CPT1a阳性染色面积占比增加;线粒体形态异常及网络损伤改善,P均<0.05。GW9662组较吡格列酮组室性心律失常诱发率较高、VERP缩短、ARI延长;LVEF和LVFS较低;GLUT1和CPT1a阳性染色面积占比低;线粒体形态异常及网络损伤未恢复,P均<0.05。结论:吡格列酮可降低β1AAb诱导的室性心律失常,改善心室电传导和激动恢复时间异质性;并可在组织病理水平缓解β1AAb所致心室重塑,并伴随心室肌糖脂转运通道蛋白的上调和受损线粒体网络的修复。

Objectives:This study aims to explore the effects of pioglitazone on the attenuation of ventricular arrhythmias(VAs)induced byβ1-adrenergic receptor autoantibodies(β1AAb)and its potential mechanisms.Methods:48 SD rats were uniformly randomly divided into four groups using number table:control group received vehicle injection,β1AAb group received back multi-point injection ofβ1AR-ECLⅡantigen peptide with adjuvant,2 mg/(kg·time),pioglitazone group received pioglitazone gavage for 2 weeks after 8 weeks of immunization,4 mg/(kg·d),and GW9662 group received pioglitazone+GW9662 intraperitoneal injection for 2 weeks after 8 weeks of immunization,1 mg/(kg·d).Powerlab recorded electrocardiograms and blood collection every 2 weeks.Baseline and week 10 echocardiography were recorded,followed by electrophysiology,histopathology,immunohistochemical staining,and electron microscopy examination after 10 weeks.Results:Compared to control group,β1AAb group showed a higher incidence of ventricular arrhythmias,shorter ventricular effective refractory period(VERP),longer action-recovery interval(ARI),lower left ventricular ejection fraction(LVEF)and left ventricular fractional shortening(LVFS),lower positive staining area ratio of glucose transporter 1(GLUT1)and carnitine palmitoyltransferase 1a(CPT1a),all P<0.05.Mitochondrial morphology abnormalities and network damage were also significantly observed(P<0.05).In contrast toβ1AAb group,pioglitazone group showed a reduced incidence of ventricular arrhythmias,prolonged VERP,shortened ARI,recovered LVEF and LVFS,increased the positive staining area ratio of GLUT1 and CPT1a,all P<0.05.Improvement was observed in mitochondrial morphology abnormalities and network damage(P<0.05).Compared to pioglitazone group,GW9662 group exhibited a higher incidence of ventricular arrhythmias,shorter VERP,and longer ARI,lower LVEF and LVFS,lower positive staining area ratio of GLUT1 and CPT1a,all P<0.05.Mitochondrial morphology abnormalities and network damage did not recover(P<0.05).Conclusions:Pioglitazone can reduce VAs induced byβ1AAb,improve ventricular electrical conduction and activation recovery time heterogeneity,and mitigate ventricular remodeling caused byβ1AAb at the tissue pathology level,accompanied by upregulation of ventricular cardiomyocyte glucose and lipid transport channel proteins and repair of damaged mitochondrial networks.