MORPHOMETRY OF MEDIAL HYPERTROPHY IN THE RAT THORACIC AORTA

  • 1 January 1980
    • journal article
    • research article
    • Vol. 42  (5) , 559-565
Abstract
Surgical constriction of the subdiaphragmatic aorta in young adult male rats induced a 54% hypertrophy (39% thickening) of the wall of the thoracic aorta in 8 days, with no increase in the number of elastic lamellae. Morphometric analysis of the aorta wall showed volume increases of its component smooth muscle cells (57%) elastic laminae (30%), collagen (136%) and endothelium plus subendothelial space (40%). Mean cell volume of smooth muscle cells increased 55% from 272 .+-. 11 to 421 .+-. 21 .mu.m3 (P < 0.005). The number of smooth muscle cells per cm of length of thoracic aorta was 4.2 .+-. 0.3 .times. 106 in both control and experimental animals. Aortic medial hypertrophy following aortic stenosis included enlargement but no proliferation of smooth muscle cells. Absolute volume increases in the average smooth muscle cell included the nucleus (27%), myofilaments (47%), mitochondria (62%), rough endoplasmic reticulum (246%), smooth endoplasmic reticulum (23%) and caveolae (37%).