CAJ | 학술논문

目的：探讨糖尿病心肌病(DCM)大鼠心室肌细胞瞬时外向钾电流(Ito)的变化，了解其在电重构中的作用。方法选用20只健康成年SD大鼠，随机分为对照组(n=10)和DCM组(n=10)，并通过病理组织学证实为DCM心肌病理学改变。分别对两组大鼠采用改进的耐钙成年大鼠急性酶分离方法分离心肌细胞，运用膜片钳技术以全细胞模式分别记录两组大鼠心室肌单细胞的Ito和膜电容，并分析比较两组大鼠心室肌Ito的变化。结果与对照组比较，DCM组大鼠左心室心肌细胞的Ito电流密度显著低于对照组[+70 mV时，(16.80±9.10) pA/pF v s(36.25±5.20)pA/pF](P<0.05)，DCM组的Ito的I-V曲线明显较对照组下移。结论 DCM的Ito数量明显减少，在DCM心肌电重构中起着重要作用。 Ito的减少及Ito通道的分布密度不同，可导致动作电位时程与有效不应期发生变化，可能与临床严重心律失常的发生有关。
목적：탐토당뇨병심기병(DCM)대서심실기세포순시외향갑전류(Ito)적변화，료해기재전중구중적작용。방법선용20지건강성년SD대서，수궤분위대조조(n=10)화DCM조(n=10)，병통과병리조직학증실위DCM심기병이학개변。분별대량조대서채용개진적내개성년대서급성매분리방법분리심기세포，운용막편겸기술이전세포모식분별기록량조대서심실기단세포적Ito화막전용，병분석비교량조대서심실기Ito적변화。결과여대조조비교，DCM조대서좌심실심기세포적Ito전류밀도현저저우대조조[+70 mV시，(16.80±9.10) pA/pF v s(36.25±5.20)pA/pF](P<0.05)，DCM조적Ito적I-V곡선명현교대조조하이。결론 DCM적Ito수량명현감소，재DCM심기전중구중기착중요작용。 Ito적감소급Ito통도적분포밀도불동，가도치동작전위시정여유효불응기발생변화，가능여림상엄중심률실상적발생유관。
Objective To investigate the changes of the transient outward potassium current (Ito) on ventricular my-ocardium in diabetic cardiomyopathy (DCM) rat and to explore the meaning of theses changes for ventricular electro-physiological remodeling. Methods 20 healthy adult Spprague-dawley rats were selected and randomly divided into control group (n=10) and DCM group (n=10).The myocardial pathological alterations of DCM were identified in DCM group by histopathologic test,and cardiomyocytes in both groups were separated by advanced calcium-tolerant separa-tion method.Whole-cell path clamp technique was used to record the unicellular changes of Ito and membrane capaci-tance in left ventricular myocytes for DCM and control group respectively.All data were analysed and compaired by software. Results Compared with control group,the Ito density on left ventricular myocytes was significantly lower in DCM group than that of the control group [(16.80±9.10) pA/pF vs (36.25±5.20) pA/pF,at +70 mV](P<0.05),and the I-V curve of Ito in DCM group was more depressed than the control group markedly. Conclusion The changes of Ito play an important role in cardiac electrophysiological remodeling of diabetic cardiomyopathy.The reduction of Ito and the variations of Ito density may be lead to the modifications of action potential duration and effective refractory period, which associates with severe arrthymia.