心肌肥厚大鼠超声背向散射积分与细胞外基质重塑相关性的研究(英文)

Ultrasonic backscatter in cardiac hypertrophy

目的探讨心肌肥厚大鼠背向散射积分的变化情况,并结合心肌细胞外基质的病理改变及其重要影响因子基质金属蛋白酶(MMP-9)和其生理性抑制剂(TIMP-1)在蛋白和基因水平的表达,探讨其相互关系。方法SD大鼠腹腔注射去甲肾上腺素[1.06 mg/(kg·d)×15 d]建立心肌肥厚的动物模型,测定室间隔中部心肌的背向散射参数,并应用免疫组化和逆转录一聚合酶链反应法(RT-PCR)方法检测心肌总体胶原、Ⅰ型和Ⅲ型胶原的改变,及MMP-9,TIMP-1蛋白和mRNA的表达,与超声测定的结果进行对比研究。结果(1)实验组大鼠心肌胶原成份及MMP-9,TIMP-1的表达显著高于健康对照组(P<0.01)。(2)超声背向散射积分(IBS%)在实验组较对照组高(P<0.01),与心肌胶原、MMP-9和TIMP-1的表达之间存在相关性。结论大鼠心肌肥厚时IBS%升高与胶原的过渡沉积密切相关,而MMP-9和TIMP-1可能是引起心肌细胞外基质重塑的重要机制之一。

Objective: To investigate the relations between myocardial ultrasonic integrated backscatter (IBS) an cardiac extracellular matrix (ECM) remodeling and expression of matrix metalloproteinase (TIMP-1) in rats with norepinephrine-induced cardiac hypertrophy. Methods: The rats model which was established by norepinephrine (NE 1.06 mg/(kg·d) were injected intraperitoneally twice a day for 15 days. Cardiac hypertrophy and extracellular matrix remodeling were evaluated by analysis of ultrasonic backscatter signal and morphological examination. The mRNA and protein expression of MMP-9 and TIMP-1 were examined by immunohistochemical and reverse transcription-polymerase chain reaction (RT-PCR) analysis. Results: The cardiac collagen and expression of MMP-9 and TIMP-1 were significantly increased in NE group compared with control group (P <0.01). Myocardial integrated backscatter (IBS) was increased in NE group, and was directly related to cardiac collagen and the mRNA and protein expression of MMP-9 and TIMP-1. Conclusions: There are good correlations between ultrasonic integrated backscatter parameters and changes of extracellular matrix. MMP-9 and TIMP-1 may play an important role in the cardiac ECM remodeling.