Mechanical production of pleural cysts in isolated rat lungs: an experimental model for pleural blebs

In an effort to establish the pathogenesis and developmental mechanisms of pleural blebs, which are not well understood, I attempted to produce bleb-like lesions experimentally in isolated rat lungs, and observed them histologically and ultrastructurally. One to 2 ml of the Dulbecco's phosphate-buffered saline or a mixture of sodium citrate, citric acid and dextrose was injected in usual speed into the subpleural lung parenchyma while the hilum of the lung was lightly pinched with forceps. This treatment induced one of two kinds of pleural cysts near the site of injection; one, in which a space was produced between the pleural connective tissues and lung parenchyma, and the other, in which it was between mesothelial cell layer and the pleural connective tissues. These observations suggested that some of the blebs in humans may arise on mechanical stress, and that there may be two different types of blebs in humans, too.