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为研究人心糜酶(hChymase)在心脏血管紧张素Ⅱ(angiotensinⅡ, AngⅡ)形成中的作用及在心肌重塑过程中的意义, 建立了MLC2-人心糜酶转基因小鼠. 用RT-PCR方法分析了糜酶基因的组织特异性表达和心脏中Ⅰ, Ⅲ型胶原基因的转录表达, 并用放射免疫法检测了心脏糜酶及血管紧张素转换酶(angiotensin converting enzyme, ACE)活力以及心脏和血浆的AngⅡ含量, 用明胶酶谱法检测了心脏基质金属蛋白酶(matrix metalloproteinase, MMP)活力; 并对糜酶转基因小鼠的心脏肥大表型用生理学和形态学方法进行了初步观察. 和非转基因小鼠(对照组)比较, 结果表明: (1) 糜酶转基因可在小鼠心脏中特异表达; (2) 糜酶转基因小鼠心脏糜酶活力较对照((0.27±0.07) U/mg vs (0.15±0.02) U/mg, P<0.05)显著升高, 而ACE活力不变((0.17±0.03) U/mg vs (0.18±0.02) U/mg); (3) 糜酶转基因小鼠心脏AngⅡ含量升高, 约为对照的3倍((1984±184) pg/g vs (568±88) pg/g, P<0.05), 而血浆AngⅡ含量不变((218±106) pg/mL vs (234±66) pg/mL); (4) 糜酶转基因小鼠心脏基质金属蛋白酶-9(MMP-9)活力及Ⅰ型胶原mRNA水平也显著升高(P<0.05), 而Ⅲ型胶原mRNA水平及Ⅰ/Ⅲ型胶原的mRNA比值变化不明显; (5) 糜酶转基因小鼠的血压、心率、心重/体
To study the role of hChymase in the formation of cardiac angiotensinⅡ (AngⅡ) and its significance in myocardial remodeling, a MLC2-human chymase transgenic mouse was constructed and analyzed by RT-PCR Tissue-specific expression of chymase and transcriptional expression of collagen typeⅠ and Ⅲ genes in heart were measured. The activities of cardiac chymase, angiotensin converting enzyme (ACE) and cardiac and plasma were measured by radioimmunoassay The content of AngⅡ was detected by enzyme-linked immunosorbent assay (ELISA). The cardiac matrix metalloproteinase (MMP) activity was detected by gelatin zymography. The hypertrophic phenotype of chymase transgenic mice was preliminarily observed by physiological and morphological methods. (Control group). The results showed that: (1) Chymase transgene was expressed specifically in mouse heart; (2) Chymase activity in cardiac chymase transgenic mice was (0.27 ± 0.07) U / mg vs (0.17 ± 0.03) U / mg vs (0.18 ± 0.02) U / mg); (3) AngiotensinⅡ Content increased about 3 times the control ((1984 ± 184) pg / g vs 568 ± 88 pg / g, P <0.05), while the level of plasma AngⅡ was unchanged (218 ± 106 pg / mL vs. 234 ± 66 pg / mL) The activity of matrix metalloproteinase-9 (MMP-9) and the type I collagen mRNA in the heart of mice were also significantly increased (P <0.05), while the mRNA expression of type III collagen and type Ⅰ / Ⅲ collagen did not change significantly 5) Chymase transgenic mice blood pressure, heart rate, heart weight / body