自发高血压大鼠左心室心肌胶原含量与舒张功能的相关性研究

Relationship between myocardial collagen content and cardiac diastolic function in spontaneously hypertensive rats

目的测定自发高血压大鼠(SHR)左心室心肌胶原含量和舒张功能的参数,探讨二者的相关性,并揭示它们的增龄性改变。方法雄性SHR共30只(8、14周和20周各8只,32周6只),行组织多普勒成像(TDI)检测左心室舒张功能。处死后取左心室心肌,用羟脯氨酸试剂盒测定羟脯氨酸含量;反转录-聚合酶链反应(RT-PCR)检测Ⅰ型和Ⅲ型胶原的mRNA表达。结果 TDI显示,二尖瓣环舒张早期速度(Ea)随增龄减低(P<0.05),二尖瓣环舒张早期与晚期速度比值(Ea/Aa)32周比8周时减低(P<0.01),左心室等容舒张时间(TVRT)随增龄延长(P<0.05),Tei指数随增龄增加(P<0.05)。心肌羟脯氨酸含量、Ⅰ型和Ⅲ型胶原的mRNA表达随增龄均增加(均为P<0.05)。羟脯氨酸含量、Ⅰ型和Ⅲ型胶原mRNA表达与TDI指标Ea、Ea/Aa均早负相关(r=-0.713～-0.431,P<0.001～0.05),与IVRT均呈正相关(r=0.427～0.721,P<0.001～0.01),与Tei指数均呈正相关(r=0.413～0.576,P<0.001～0.01)。结论 SHR左心室心肌胶原含量呈增龄性增加,舒张功能呈增龄性降低,二者具有相关性。

Objective To determine the changes of left ventricular myocardial collagen content and diastolic function in spontaneously hypertensive rats and disclose their relationship. Methods A total of 30 SHR （8 w, n = 8 ; 14 w, n = 8; 20 w, n = 8 and 32 w, n = 6） was performed TDI to detect left ventricular diastolic function. Rats were sacrificed. Myocardial hydroxyproline content was detected by hydroxyproline reagent and mRNA expressions of myocardial collagen type Ⅰ and Ⅲ were determined by RT-PCR. Results Ea was significantly decreased with aging （ P 〈 0. 05 ）, Ea/Aa ratio was significantly decreased in 32 w group compared with that in 8 w group （P 〈0.01 ）. IVRT was significantly prolonged with aging （P 〈0. 05）. Tei index, myocardial hydroxyproline, collagen Ⅰ and collagen Ⅲ mRNA expressions were increased with aging （P 〈 0.05）. Myocardial hydroxyproline, collagen Ⅰ and collagen Ⅲ mRNA expressions had negative correlation with Ea and Ea/Aa ratio （ r = - 0. 713 to - 0. 431, P 〈 0. 001 to 0. 01 ）, positive correlation with IVRT （r =0. 427 to 0. 721, P 〈 0. 001 to 0. 01 ） and also positive correlation with Tei index （ r = 0. 413 to 0. 576, P 〈 0. 001 to 0. 01 ）. Conclusions Left ventricular myocardial content increases with aging while diastolic function decreases with aging in SHR. These two parameters are relevant.