地尔硫卓对肾性高血压大鼠左室心肌重构的影响

Effects of diltiazem on myocardial remodeling of left ventricle in renal hypertensive rats

目的:研究地尔硫卓对肾性高血压大鼠左室心肌重构的影响,方法:建立肾性高血压大鼠模型,地尔硫卓( 100mg/kg)灌胃,q12h, 30d. 计算并比较心质量指数. 取左室壁中段组织,常规石蜡切片和超薄切片,分别观察心肌显微结构和超微结构的改变;天狼猩红染色,观察心肌胶原含量的改变和Ⅰ型/Ⅲ型胶原比值的改变. 结果:地尔硫卓可显著降低心质量/体质量比和左室质量/体质量比(降幅分别为8. 8%和9. 7%,P>0. 05),阻止心肌坏死和炎性浸润,减轻心肌细胞肥大;超微结构基本正常,仅在极少数视野观察到线粒体轻度增多. 地尔硫卓能显著降低胶原容积分数和平均积分光密度(降幅分别为47. 3%和69. 8%,P<0. 01),减轻Ⅰ型/Ⅲ型胶原比值增加. 结论:地尔硫卓对高血压大鼠左室重构有保护作用,显著降低胶原增生,可同时发挥降低血压和改善心脏结构的作用.

AIM: To study the effects of diltiazem on the myocardial remodeling of left ventricle in renal hypertensive rats (RHR). METHODS: RHR model was established and received diltiazem (100 mg/kg, ig) q12 h continuously for 30 d. The index of the heart mass was compared between groups. A piece of tissue from the middle of the left ventricle was harvested, and the paraffin section and ultrathin section were prepared routinely and the microstructural and ultrastructural changes were observed respectively. Picrosirus red staining was performed and the changes of the collagen contents and of type Ⅰ to type Ⅲ ratio were determined. RESULTS: Diltiazem decreased the ratios of heart mass/body mass and left ventricle mass/body mass slightly (by 8.8% and 9.7% respectively, P >0.05), kept the myocardium out of necrosis and inflammatory infiltration, and alleviated the myocardial hypertrophy. The ultrastructure was almost normal and only very few fields with slightly proliferated mitochondria were observed. Diltiazem reduced the collagen volume fraction and the integrity optical density significantly (by 47.3 % and 69.8 % respectively, P <0.01), and kept the ratio of collagen type Ⅰ to collagen type Ⅲ from increasing. CONCLUSION: Diltiazem plays protective roles during the left ventricle remodeling of hypertension, especially in attenuating the hyperplasia of collagen. It reduces the blood pressure and improves the myocardial structure simultaneously.