论文部分内容阅读
背景泛素蛋白酶体系统(UPS)是ATP依赖性的、非溶酶体蛋白质的降解通路,在扩张型心肌病、压力负荷引起的心力衰竭中泛素化蛋白积聚,存在着蛋白酶体功能损害,而在缺血性慢性心力衰竭中UPS的变化尚未见报道。目的研究UPS在缺血性慢性心力衰竭中的变化。方法雄性GFPdgn转基因小鼠,通过缝扎冠状动脉左前降支制作慢性心力衰竭模型,随机分为冠状动脉结扎术后1周组(MI-1)和3周组(MI-3),每组取16只制模成功小鼠进行实验。16只转基因小鼠开胸,撕开心包,不结扎冠状动脉,作为对照组。超声心动图测定心脏参数,荧光底物测定糜蛋白酶样(Ch-TL)活性,应用免疫荧光标记共聚焦显微镜法检测心肌组织泛素化蛋白,Westernblot法检测心肌组织泛素化蛋白和26S蛋白酶体亚单位蛋白表达水平。结果冠状动脉结扎后,左室舒张末内径(LVDd)、左室收缩末内径(LVDs)增加[LVDd:MI-1(0.37±0.05)、MI-3(0.40±0.07)比对照组(0.31±0.02)cm;LVDs:MI-1(0.28±0.03)、MI-3(0.31±0.05)比对照组(0.17±0.03)cm;P<0.05或0.01],短轴缩短率降低[MI-1(23.5±5.2)%、MI-3(22.3±5.5)%比对照组(49.5±7.8)%;均P<0.01]。与对照组相比,Ch-TL活性在MI-1和MI-3组分别降低约27%和56%(P<0.01)。MI-3组心肌细胞泛素化蛋白积聚,肌丝破坏,且26S蛋白酶体亚单位β1、β2、β5、Rpt5和Rpn2蛋白表达均较对照组明显下降。结论缺血性慢性心力衰竭时UPS功能异常,其蛋白转运和降解过程均存在缺陷。
Background The ubiquitin proteasome (UPS) is an ATP-dependent, non-lysosomal protein degradation pathway that accumulates ubiquitinated proteins in dilated cardiomyopathy, stress-induced heart failure, and impaired proteasome function, In the ischemic heart failure in UPS has not been reported changes. Objective To study the changes of UPS in ischemic heart failure. Methods Male GFPdgn transgenic mice were randomly divided into 1 week group (MI-1) and 3 weeks group (MI-3) after coronary artery ligation, by means of suture of the left anterior descending branch of coronary artery for chronic heart failure. Sixteen successful mice were modeled. Twenty-six transgenic mice were thoracotomy, pericardium ripped and coronary arteries were not ligated as a control group. Cardiac parameters were measured by echocardiography, cholinesterase (Ch-TL) activity was measured by fluorogenic substrate, and ubiquitinated protein was detected by immunofluorescence-labeled confocal microscopy. The expression of ubiquitinated protein and 26S proteasome Subunit protein expression levels. Results LVDd and LVDs increased after coronary artery ligation (LVDd: MI-1 (0.37 ± 0.05) vs MI-3 (0.40 ± 0.07 vs 0.31 ± 0.02) cm; LVDs: MI-1 (0.28 ± 0.03), MI-3 (0.31 ± 0.05) vs control (0.17 ± 0.03) cm; P <0.05 or 0.01] 23.5 ± 5.2)%, MI-3 (22.3 ± 5.5)% than the control group (49.5 ± 7.8)%, all P <0.01]. Ch-TL activity was reduced by about 27% and 56%, respectively, in the MI-1 and MI-3 groups compared to the control group (P <0.01). Myocardial cell ubiquitinated protein accumulation and myofilament destruction were observed in MI-3 group, and the expressions of β1, β2, β5, Rpt5 and Rpn2 in 26S proteasome subunits were significantly lower than those in control group. Conclusions UPS function abnormalities in ischemic heart failure, and its protein transport and degradation process are flawed.