压力负荷增加大鼠模型心肌Ⅰ型和Ⅲ型胶原mRNA的表达

The expression of myocardial collagen type Ⅰand type Ⅲ mRNA in rat with pressure overload

目的观察压力负荷增加大鼠心肌Ⅰ型和Ⅲ型胶原mRNA的表达,探讨压力负荷增加大鼠模型心肌纤维化的分子机制。方法SD大鼠随机分为假手术组和模型组(手术组),利用腹主动脉缩窄法制备压力负荷增加大鼠模型,造模8周后观察左室心肌病理形态胶原染色、左室心肌间质超微结构等心肌纤维化指标的改变;采用RT-PCR的方法检测心肌组织α2(Ⅰ)胶原、α2(Ⅲ)胶原的基因表达。结果假手术组造模后左室心肌胶原染色在心肌细胞间仅有少许鲜红色胶原纤维;模型组造模后左室心肌病理形态胶原染色显示心肌细胞间有大量的鲜红色胶原纤维存在;左室心肌细胞超微结构也见明显异常改变。模型组大鼠左室心肌组织α2(Ⅰ)胶原mRNA表达较假手术组上升(P<0.01),左室心肌组织α2(Ⅲ)胶原mRNA表达较假手术组上升(P<0.05)。结论压力负荷增加大鼠在造模8周后即已形成心肌纤维化的病理生理改变,该改变可能主要是通过降低α2(Ⅰ)型胶原和α2(Ⅲ)型胶原基因表达来实现的。

Objective To observe the expression of myocardial collagen type Ⅰ mRNA and Ⅲ mRNA in rat with pressure overload,study the mechanism of regressing left ventricular hypetrtophy, and study the molecular mechanism of regressing myocardial fibrosis. Methods SD male rats were randomly divided into sham operation group and model group. The aorta was damped above the suprarenal abdominal aortic by silver chip in model group ;the changes of left ventrieular myoeardium collagen pathological coloring and the left ventricular interstitial cardiac tissue ultra mierostructure were observed after 8 weeks, RT-PCR was used to detect the gene expression of type α2 （ Ⅰ ） collagen and type α2 （ Ⅲ ） collagen in myocardial tissue. Results The type α2（ Ⅰ ）collagen mRNA expression of left ventricular myocardial tissue in model group was higher than that of sham operation group （P〈0. 01 ）. The type α2 （ Ⅲ ）eollagen mRNA expression of left ventricular myocardial tissue in model group was higher than that in sham operation group（P〈0. 05）. Condusion The main physiopathologie changes of myocardial fibrosis were formed in the rat with pressure overload by abdominal aortic constriction after 8 weeks, this change of myocardial fibrosis maybe related to the upregulation of the gene expression of type α2 （ Ⅰ ） collagen and type α2 （ Ⅲ ） collagen.