- Startpagina tijdschrift
- Volume 4 (1985)
- Number 2 - Proceedings of the fourth European symp...
- Different stereological reaction patterns of the myocardium in hypertrophy induced by exercise and pressure overload
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Different stereological reaction patterns of the myocardium in hypertrophy induced by exercise and pressure overload
Abstract
Mild cardiac hypertrophy was induced in young female rats by an exercise model and in young male rats by surgical stenosis of the left renal artery. Two randomly selected transverse and longitudinal sections per animal of the left ventricular papillary muscles were studied after fixation by vascular perfusion. Estimates of length density and surface density were corrected for partial anisotropy by means of the Dimroth-Watson orientation distribution. In both models the myocardial cells showed an increase of mean cross-sectional area with unchanged quantitative cytoplasmic ultrastructure. At exercise induced hypertrophy Vv, Sv and Lv of capillaries per tissue volume remained unchanged, whereas all these estimates were significantly decreased at hypertrophy induced by pressure overload. Consequently 3D capillary-fiber ratio was increased at exercise-induced hypertrophy only. The result is discussed as capillary proliferation incited by increased myocardial perfusion at exercise.