心房肌基质金属蛋白酶及其抑制剂、凋亡相关基因表达改变与增龄性心房颤动关系的研究

摘要

目的：本研究目的是为论证在增龄性心房颤动（房颤）时基质金属蛋白酶-9链（MMP-9）与基质金属蛋白酶抑制剂-1（TIMP-1）、抗凋亡基因（BCL-2）与促凋亡基因（BAX）的表达改变是否与心房结构重构有关，以期为增龄性房颤的发病机制及药物干预提供可能的策略与思路。　　方法：通过持续快速心房起搏建立慢性房颤犬模型，用实时荧光定量聚合酶链反应（PCR）和蛋白免疫印迹（Western blot）方法检测4组犬（成年窦性心律犬，老年窦性心律犬，成年慢性房颤犬，老年慢性房颤犬各7只） MMP-9与TIMP-1、BCL-2与BAX在mRNA和蛋白质表达水平变化。应用光镜、电镜及TUNEL法分别检测细胞结构重构和细胞凋亡。　　结果：与成年窦性心律犬比较，老年犬MMP-9和BAX在mRNA和蛋白质的表达均显著地增高（P<0.05），而TIMP-1和BCL-2的表达均显著地下降（P<0.05）；与窦性心律犬比较，房颤犬MMP-9和BAX表达水平均显现出有意义的上调趋势（P<0.05），尤其是老年房颤犬最为明显；TIMP-1和BCL-2表达水平均显现出有意义的下调趋势（P<0.05），尤其是老年房颤犬最为明显。伴随老龄与房颤，犬心肌纤维化程度、细胞超微结构及凋亡指数均显现出有统计学意义的改变。　　结论：伴随增龄与房颤而显现的MMP-9与TIMP-1，BCL-2与BAX改变可能是增龄性房颤心房重构的分子机制之一。%Objective: To explore the relationship between atrial MMP-9 with its inhibitor (TIMP-1), anti-apoptosis gene (BCL-2) with apoptosis gene (BAX) and the aging with atrial remodeling in experimental dog model during atrial ifbrillation (AF), in order to better deal with the aging caused AF. Methods: The experimental dogs were divided into 4 groups: ①Adult with sinus rhythm (ASR) group, ②Elder with sinus rhythm (ESR) group and③Adult with AF (AAF) group,④Elder with AF (EAF) group. n=7 in each group. Chronic AF model was induced by rapid and persistent atrial pacing. The mRNA and protein expressions of MMP-9, TIMP-1 and BCL-2, BAX were measured by real time quantitative RT-PCR and Western blot analysis. The cellular ultra structural remodeling was examined by optical/electron microscopy, and the apoptosis index was determined by TUNEL method, Results: Compared with adult dogs, the elder dogs showed obviously increased expressions of MMP-9, BAX, and decreased expressions of TIMP-1, BCL-2, all P<0.05. Compared with SR gods, the AF dogs presented up-regulated expressions of MMP-9, BAX, all P<0.05, and down-regulated expressions of TIMP-1, BCL-2, all P<0.05, such changes were most obvious in elder AF dogs. Accompanying with the aging and AF, the degree of atrial ifbrosis, cellular ultra structure and the apoptosis index were changed with the statistic meaning. Conclusion: The abnormal expressions of MMP-9/TIMP-1 and BCL-2/BAX might be one of the molecular mechanisms for aging caused AF in experimental dog model.