【作者】 胡咏梅；

【导师】 李法琦；

【作者基本信息】 重庆医科大学 ， 内科学， 2003， 硕士

【摘要】 目的： 构建后负荷增高型充血性心力衰竭大鼠模型，研究心肌细胞凋亡和内皮素-1的变化及其意义，以及二者对心室重构、心功能的影响。应用卡维地洛和阿替洛尔对心衰大鼠进行干预，观察心肌细胞凋亡及内皮素-1基因表达的变化，并对其作用机制进行探讨。方法： 采用腹主动脉缩窄术构建心衰模型，30只雌雄各半的Wistar大鼠随机分为：①心衰组(n=10)，②阿替洛尔组(n=10)，③卡维地洛组(n=10)，同时设立假手术组(n=10)。药物干预4周，左心室导管测定血流动力学指标(HR, MBP, LVSP, LVEDP, ±dp/dtmax)，观察左、右心室质量指数(LVMI, RVMI)，检测氧自由基代谢指标(SOD, MDA)，TUNEL法检测凋亡心肌细胞(AI)，RT-PCR半定量检测心肌组织内皮素-1基因的表达。结果： (1)与假手术组比较，心衰组血流动力学指标明显恶化(P<0.01-0.05)；LVMI和RVMI显著升高19.8%和40.7%(p<0.001-0.01)，光镜下见心肌实质、间质结构改变；血清SOD活性下降、MDA含量明显增加(P<0.01-0.05)；心肌细胞凋亡率显著增加(p<0.001)，内皮素-1基因过度表达(p<0.001)，二者显著正相关 (r=0.698，p<0.05)。(2)心衰组心肌细胞凋亡率和内皮素-1基因的表达与LVMI均呈正相关(r=0.767，0.672，P<0.01-0.05)，且二者与心衰恶化程度相平行(p<0.001-0.05)；心肌细胞凋亡程度和内皮素-1基因表达水平与血清SOD活性负相关(r=-0.636，-0.744，P<0.02-0.05)，而与MDA含量正相关(r=0.701，0.836，P<0.01-0.05)。(3)阿替洛尔治疗后MBP及LVEDP下降(p<0.01-0.05)，-dp/dtmax升高(p<0.01-0.05)；阿替洛尔组心肌细胞凋亡率下降(p<0.05)；而LVMI和RVMI、SOD和MDA及心肌组织内皮素-1基因表达与心衰组无显著性差异(p>0.05)。(4)卡维地洛干预后MBP及LVEDP下降(p<0.01-0.05)，LVSP和±dp/dtmax 均升高(p<0.01-0.05)；LVMI和RVMI下降；MDA含量降低，SOD活性显著增高(p<0.01-0.05)；心肌细胞凋亡指<WP=7>数下降，心肌组织内皮素-1基因表达下调(p<0.01-0.05)。与阿替洛尔组相比，卡维地洛减少心肌细胞凋亡更为明显(p<0.01)。 结论： (1)在体心衰模型中氧自由基代谢障碍，心肌组织内皮素-1基因表达上调，心肌细胞凋亡增强。(2)内皮素-1可能是促进心肌细胞凋亡的因素，干扰内皮素-1的生成可能是抗心肌细胞凋亡一个新的治疗靶点。(3)细胞凋亡和内皮素-1均参与心室重构，心肌细胞凋亡率和内皮素-1基因表达水平提示心衰远期预后。(4)阿替洛尔改善衰竭心脏舒张功能，抑制心肌细胞凋亡。(5)卡维地洛较阿替洛尔更有效地改善衰竭心脏功能，逆转心室肥厚，有利于改善心衰远期预后，其机制可能与卡维地洛清除氧自由基，减少心肌细胞凋亡及下调内皮素-1表达有关。更多还原

【Abstract】 OBJECTIVE: Using over-afterloaded congestive heart failure rats as experimental model, to study the relationship between myocardial apoptosis and cardiac endothelin-1 gene expression and their effects on ventricular remodeling and heart function, and to investigate the intervention of carvedilol and atenolol on heart failure rats. METHODS: Partially banding abdominal aortic artery to achieve congestive heart failure rats model, 30 Wistar-Kyoto rats were randomly divided into three groups: ①heart failure group(n=10), ②atenolol group(n=10), ③carvedilol group(n=10). Sham-operated group(n=10) was set up as a control one. After 4 weeks of medicine intervention, hemodynamic parameters, left and right ventricular mass index, serum SOD and MDA, myocardial apoptosis and expression of preproendothelin-1 gene were determined in each group. RESULTS: (1)Compared with sham-operated group, hemodynamic parameters were deteriorated(P<0.01-0.05), and LVMI and RVMI were risen up by 19.8% and 40.7%, respectively, in heart failure group(p<0.001-0.01).　Under optical microscope, myocyte hypertrophy, myocardial cell degeneration, extensive areas of interstitial, inflammatory cell infiltrate were seen in heart failure rats; in heart failure rats, serum SOD activity was descended while MDA was ascended(P<0.01-0.05); myocardial apoptosis was increased significantly(p<0.001), and endothelin-1 gene was over-expressed(p<0.001). In addition, there was positive correlation between<WP=9>myocardial apoptosis and endothelin-1 gene expression(r=0.698, p<0.05). (2)In heart failure group, there was a strong relationship between LVMI and endothelin-1(r=0.672, p<0.05), so between LVMI and myocyte apoptosis (r=0.767, P<0.01); cardiomyocyte apoptosis and endothelin-1 gene expression were associated with failured heart hemodynamic parameters(p<0.001-0.05); both cardiac apoptosis index and endothelin-1 gene expression were negatively related to SOD activity(r=-0.636, -0.744，P<0.02-0.05) and positively to MDA content(r=0.701,0.836，P<0.01-0.05). (3)In comparison with heart failure rats, HR, MBP and LVEDP were decreased and -dp/dtmax was increased after atenolol therapy(p<0.01-0.05); myocardial apoptosis index was reduced obviously(p<0.05). However, there were no significant difference on LVMI and RVMI, SOD and MDA, and cardiac endothelin-1 gene expression in atenolol group. (4)HR, MBP and LVEDP were descended, and LVSP and ±dp/dtmax were ascended (p<0.01-0.05); LVMI and RVMI were improved; serum MDA content was decreased while SOD activity was significantly increased in carvedilol group(p<0.01-0.05). After carvedilol intervention, myocyte apoptosis was on fallen and cardiac endothelin-1 gene was down-regulated(p<0.01-0.05). Besides, there was obvious difference between carvedilol group and atenolol group on myocardial apoptosis(p<0.01)CONCLUSIONS: (1)There are oxidation stress in congestive heart failure, and endothelin-1 gene expression and myocardial apoptosis are increased greatly. (2)Endothelin-1 may be a promotor for cardiac apoptosis, which indicates that interference of endothelin-1 production may be a novel therapeutic target for apoptosis. (3)Both cell apoptosis and endothelin-1 take part in ventricular remodeling. In addition, apoptosis and endothelin-1 have direct effects on the prognosis of heart failure. (4)Atenolol mainly improves diastolic function, and has prohibitive effect on myocardial apoptosis. (5)It is suggested that carvedilol, whose mechanism may be its elimination of oxygen radicals, attenuation of apoptosis and down-expression of endothelin-1 gene, has better protective effects than atenolol on heart failure and reverse of ventricular remodelling.更多还原