Lubricating recovery of damaged pleural mesothelium: effect of time and of phosphatidylcholines

Effect of time and phosphatidylcholines (PCs) on lubrication of damaged mesothelium has been investigated. Marked increase in coefficient of kinetic friction (μ) of pleural specimens after mesothelial blotting and rewetting decreased by 23.4 ± 3.5%, 41.8 ± 3.8%, and 40.5 ± 2.7% after 30 min, 1 h, and 2 h. Hence, damaged mesothelium is able to partially reset lubricating molecules on its surface. Increase in μ of post-blotting Ringer 2 h after addition of unsaturated PCs (3 mg/ml) decreased a little more than after 2 h Ringer. Effects of unsaturated and saturated PCs were similar, contrary to expectation raised by their different percentage in pleural and alveolar lavage. Effect of PCs did not increase at 6 mg/ml, and was nil at 0.4 mg/ml. Increase of μ after short phospholipase treatment decreased by 45.9 ± 2.0% after 2 h Ringer, and a little more after addition of unsaturated or saturated PCs. Hence, PCs, as other phospholipids, have a small effect, likely because of difficulty in resetting their relationships with main lubricating molecules.