Platelet Blockade of Particle Absorption from the Peritoneal Surface of the Diaphragm

Abstract

Abstract

Particulate material is absorbed from the peritoneal cavity via respiration-induced gaps between mesothelial cells on the peritoneal surface of the diaphragm and is then collected into diaphragmatic and retrosternal lymph vessels. The effect of platelets on this process was examined by (i) comparing the appearance of these lymph vessels after intraperitoneal (ip) injection of Radiopaque or carbon particles in control and experimental rats receiving, respectively, an ip injection of either platelet-rich (PRP) or platelet-poor (PPP) plasma or saline solution 1 hr prior to the injection of particles; and by (ii) inspecting lymph vessels on the pleural side of 20 freshly excised pieces of rabbit or dog diaphragm (secured pleural side down, to the mouth of a suction flask) 5 min after application of India ink with either PRP or PPP (or saline) to the peritoneal surface. In each case injection or application of PRP either blocked or markedly restricted particle absorption. Electron microscopic (EM) observations indicate that platelets block absorption of particles by plugging gaps between adjacent mesothelial cells.