心脏糜酶对自发性高血压大鼠心肌纤维化的影响

Effect of cardiac chymase on cardiac myoflbrosis in spontaneously hypertensive rats

目的:观察心脏糜酶对自发性高血压大鼠(SHR)心肌组织胶原合成和心肌纤维化的影响。方法:应用病理检查、计算机分析结合逆转录-聚合酶链式反应等方法,检测SHR应用糜酶抑制剂(Chy-Ⅰ)组、SHR组及Wistar Kyoto大鼠(WKY)组的收缩压、心肌胶原容积分数(CVF)、心肌血管周围胶原面积比(PVCA)和心肌糜酶及Ⅰ、Ⅲ型胶原mRNA表达。结果:Chy-Ⅰ组心脏CVF、PVCA分别为(26.8±8.7)%和0.4±0.1,SHR组分别为(46.4±7.8)%和1.9±0.9,WKY组为(24.4±10.7)%和0.4±0.1,Chy-Ⅰ组比SHR组明显下降(P<0.01),与WKY组无明显差别(P>0.05)。Chy-Ⅰ组心肌组织Ⅰ、Ⅲ型胶原和糜酶mRNA表达相对含量均明显低于SHR组(P<0.01), 与WKY组无明显差别(P>0.05)。应用Chy-Ⅰ后大鼠血压无改变。结论:心肌组织糜酶参与胶原的合成,参与细胞外基质的形成和降解,促进自发性高血压大鼠心肌纤维化。

Objective:To evaluate the effect of cardiac chymase on collagen synthesis in myocardial tissue and cardiac myofibrosis in spontaneously hypertensive rats. Methods : Using pathological examination and computer processing, the systolic blood pressure (SBP) , collagen volume fraction (CVF) and perivascu-lar circumferential area ( PVCA) of the heart in chymase inhibitor group ( Chy-Ⅰ) , SHR group and WKY group were observed. mRNA expression of chymase, Ⅰ- and Ⅲ-type collagen in myocardial tissue were analyzed using the reverse transcriptase-polymerase chain reaction. Results: The cardiac CVF, PVCA were (26.8±8.7)% and 0.4±0.1 in Chy-Ⅰ vs (46.4±7. 8)% and 1.9±0.9 in SHR group (P <0. 01, respectively). There was no significant difference between Chy-Ⅰ and WKY (P>0.05). mRNA expression of Ⅰ- and Ⅲ -type collagen and chymase in myocardial tissue were markedly decreased in Chy- Ⅰ group than in SHR group (P <0. 01, respectively) , these indexes were no significant difference between Chy-Ⅰ and WKY group (P >0. 05). No difference was observed in systolic blood pressure between Chy-Ⅰ and SHR group. Conclusion: This study supports the hypothesis that the cardiac chymase may increase collagen synthesis and participate the formation and degradation of extracellular matrix in myocardial tissue and accelerate cardiac myofibrosis in spontaneously hypertensive rats.