[Morphologic and morphometric studies of pulmonary artery endothelial abnormalities in rats induced by smoking]

Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultrastructural quantitation technique were applied to analyze the alterations of surface characteristics and intracytoplasmic composition of pulmonary artery endothelium from rats after exposure to smoking. The results showed that the important endothelial change was endothelial proliferation and intimal fibrosis. The endothelium surface comprised thick, deep, intertwined "cable-like" or "corduroy-like" ridges. Endothelial fenestrae became apparent accompanied with increased adhesion of blood elements. There was also dilation of the mitochondria with reduced numerical density, and significant increase of volume density of rough endoplasmic reticulum (P less than 0.05) microfilament (P less than 0.001) and pinocytic vesicles (P less than 0.05) in the endothelial cells, which possibly indicates the increase of endothelial metabolic function. The authors consider that the development of endothelial abnormalities may be due to increase of arterial wall thickness, causing further alteration of pulmonary hemodynamics and hemorrheology, which plays a critical role in the development of pulmonary hypertension induced by smoking in the rats.