Prevention of postoperative intrapleural adhesion of the thoracotomy incision by a bioresorbable membrane in the rat adhesion model.

For the purpose of reducing the risk of lung injury while separating adhesions in repeated pulmonary resections, the inhibitory effect of hyaluronate based bioresorbable membrane (HA membrane) on postoperative adhesions was investigated in a new pleural adhesion model in rats. First of all, a novel post-thoracotomy adhesion model in rats was successfully established by using a combination of mechanical, chemical and ischemic injuries of the pleura during operation. After undergoing the same adhesion-inducing procedures, one of two groups was treated with HA membrane inserted between the lung and the parietal pleura, and the other group underwent infusion of saline only. The severity of the adhesion formation was macroscopically lower in the HA membrane-treated rats, and they had favorable mesothelial regeneration microscopically. Additionally, the activity of type 1 plasminogen activator inhibitor (PAI-1) in the intrapleural lavage fluid (ILF) was measured at 24 hours postoperatively because this is the main influence on adhesion formation after surgery. PAI-1 activity was 23.37+/-2.57 U/ml in the saline-treated group and 17.85+/-3.06 U/ml in the HA membrane-treated group. The result suggests that the HA membrane inhibits postoperative adhesion formation through a significant repression of PAI-1 activity.