压力负荷增高性心肌肥厚大鼠心肌胶原网络重构及Ⅰ, Ⅲ型胶原mRNA表达的变化

Remodeling of collagen network and Types Ⅰ,Ⅲ collagen gene expressions in rat myocardium with pressure-overloaded hypertrophy

目的 :探讨压力负荷增高性心肌肥厚时心肌胶原网络的重构及心肌 , 型胶原基因表达的变化。方法 :腹主动脉部分结扎术致大鼠心肌肥厚 ,VG染色和图象处理观察心肌胶原网络重构 ,Northern杂交测定心肌 , 型胶原基因表达。结果 :手术组大鼠术后 1周即呈现心肌肥厚 ,其程度随时间进展而加重。与假手术组比较 ,左室心肌总胶原容积百分比 (CVF- T)于术后 2周增高 ,CVF- T和无小血管视野胶原容积百分比 (CVF- NV)于术后 4,8周均显著增高 (P<0 .0 1)。左室心肌组织 , 型胶原 m RNA的表达于术后 1周明显增高 , 型胶原 m RNA的表达于术后 4周至假手术组水平 ,而 型胶原 m RNA表达则于术后 8周降至假手术组水平。结论 :压力负荷增高性心肌肥厚形成过程中伴有心肌胶原网络的重构 ,心肌 , 型胶原 m RNA表达增加可能是心肌胶原合成增加致心肌胶原网络重构的原因之一。

AIM:To investigate collagen network remodeling and changes in collagen Types Ⅰ and Ⅲ gene expressions in hypertrophied rat myocardium. METHODS:The artial abdominal aorta ligature was used to induce hypertrophy in rats. Myocardial collagen was stained with VG and analyzed by means of a computer assisted procedure. Types Ⅰ and Ⅲ collagen gene expressions were assessed with Northern blot. RESULTS:The operated rats manifested myocardial hypertrophy only 1 week after the operation. With time passing, myocardial hypertrophy became severer. In comparison with those of the sham-operated rats,the myocardial total-collagen volume fraction(CVF-T) increased 2 weeks after the operation(P<0.05), CVF-T and nonvascular-collagen volume fraction(CVF-NV) both increased significantly 4 and 8 weeks after the operation(P<0.01). Types Ⅰ and Ⅲ collagen gene expressions of the left ventricular myocardium increased significantly 1 week after the operation,the gene expression of Type Ⅰ decreased to the level of the sham-operated rats 4 weeks after the operation,while that of Type Ⅲ decreased to of the level sham-operated rats 8 weeks after the operation. CONCLUSION:Myocardial collagen network remodeling occurs during the development of pressure-overloaded myocardium hypertrophy. The increase of Types Ⅰ and Ⅲ collagen gene expressions is probably one of the causes of the enhancement of the synthesis of myocardium collagen and induction of myocardial collagen network remodeling.