Morphometry of the amount of smooth muscle cells in the media of various rabbit arteries.

Our objective in this study was to evaluate the relative amount of smooth muscle cells in the medial layer of various rabbit arteries. The fixation of smooth muscle cells in the arterial wall is difficult and the differential effect of glutaraldehyde (GA) and fixative vehicle on cell ultrastructure in different tissues is controversial. We compared the effect of various concentrations of the vehicle and glutaraldehyde (osmolarity ranges for total fixative, 350-1030 mOsm) on the arterial wall ultrastructure. We found that a 600 mOsm GA solution (isotonic vehicle; 2.5% GA) adequately preserves arterial wall structures. The relative amount of smooth muscle cells in the media differed in various segments along the arterial tree. It ranged from 35% (thoracic aorta) to 74% (tibial artery). The importance of weighting the contractile response of different arteries in vitro to their relative smooth muscle cell content is discussed.