CHANGES OF MYOCARDIAL COLLAGEN DURING REGRESSION OF HYPERTENSIVE CARDIAC HYPERTROPHY IN RATS

Objective:To investigate the changes in ultramicro-structure of myocardial collagen network during regression of hypertensive cardiac hypertrophy,so as to provide theoretical basis for clinical therapy.Methods: Hypertensive model in rats was established, and regression of cardiac hypertrophy was induced by daily intake of captopril(30 mg·kg -1 )4 weeks later for 12 weeks.BP and HR were recorded with polygraph channel system,and ultramicro-structure of myocardial collagen network were observed by transmission electromicroscopy.Results:(1)Systolic blood pressure,diastolic blood pressure and mean arterial pressure in hypertension group were higher than those in control groups(shammed operation control and normal control)before and 4, 8 weeks after regression,and were not significantly different from those in controls 12 weeks later.(2)Severe pathological changes in myocardio-interstitial collagen matrix network including sedimentation of protein in network were found before regression, and gradually diminished after regression. The changs were not uniform, somewhere became nearly normal 12 weeks later.Conclusions: Sedimentation of protein in collagen matrix network is one of the pathological changes in hypertensive cardiac hypertrophy. The effect of captopril on hypertensive cardiac hypertrophy is mainly to reduce protein sediment in collagen network.