Effects of Benazepril on different phases of myocardial fibrosis

Objective To determine the angiotensin converting enzyme inhibitor Benazepril on reactive and reparative myocardial fibrosis in renovascular hypertensive rats. Methods Two kidney, one clip renovascular hypertensive rats were constructed. Rats were randomly divided into hypertensive groups and control groups after 4, 12 and 20 weeks. Low dose (7.5 mg·kg -1 ·d -1 ) and high dose (15 mg·kg -1 ·d -1 ) of Benazepril were given respectively to 12 weeks and 20 weeks hypertensive rats for 8 weeks. Systolic blood pressure, LV/BW, CVF and PVCA were measured. Collagen concent by improved Bergman's method and collagen type Ⅰto type Ⅲ ratio(Ⅰ/Ⅲ) by polyacrylamide electrophoresis were detected. Results During reactive fibrosis, regression in left ventricular hypertrophy(LVH) and collagen deposition were achieved by treatment with low dose Benazepril. However, during reparative fibrosis, LVH regression was observed in high dose Benazepril, only collagen deposition was alleviated. The two dosages of Benazepril normalized the ratio of collagen Ⅰto Ⅲ in the two phases. Conclusions Benazepril can diminish the amount of collagen to some extent, and be beneficial to regression of myocardial fibrosis when treated early.