Laser-induced shock wave endothelial cell injury.

Abstract

Several laser procedures, extracorporeal lithotripsies (ESWL), and high-velocity missile trauma generate pressure transients that are transmitted through the tissues. Despite several publications demonstrating shock wave-induced tissue injury, little is known about its pathophysiology. This study introduces an in vitro model for studying shock wave effects on endothelial cell (EC) monolayers. A Nd:YAG laser-driven flyer-plate technique was used to generate shock waves. Physical characteristics were determined with a pressure transducer, a high-speed video camera, and sequential photography. Biological effects were studied with phase contrast and lightfield microscopy, computerized morphometry, immunocytochemistry, spectrophotometry, and enzyme-linked immunosorbent assay (ELISA). The shock waves generated were highly reproducible. Cavitation was verified and quantified, and its extent could be varied in the vials. Exposed cultures exhibited areas with cell membrane damage and cell detachment. Release of LD was elevated (P < 0.01) in exposed vials. The EC lesions were larger (>P < 0.01) in cultures submitted to high vs. low extent of cavitation. The flyer-plate model can be used to subject cell monolayers to defined and reproducible shock waves causing immediate cell injury similar to the previously reported vascular lesions associated with ESWL, pulsed lasers, and blast trauma. With the flyer-plate model, such lesions may be further studied on the cellular and subcellular levels.