Endothelial damage by bubbles in the pulmonary artery of the pig.

A method for measuring endothelial damage caused by decompression was developed for vessels with a large radius. Segments of the pulmonary artery from pigs (8-12 wk old) were tested for endothelium damage using a system for recording changes in the tension in the vessel wall. Substance P (SP) was used as an endothelial-dependent dilation agonist. A significant decrease was found in the total response (Tmax) for SP as a result of endothelium damage, and the reduction in response was related to the number of bubbles. Furthermore, the sensitivity of the vessels to the agonist was significantly reduced after exposure to bubbles. Staining the endothelium with silver nitrate and light microscopy confirmed mechanical endothelium damage.