The regional difference of pleural mesothelial cells in rabbits.

Abstract

The pleura of rabbits was studied using both scanning and transmission electron microscopes. Mesothelial cells were either bumpy or flattened, usually reflecting the rigidity of the structure underneath. Microvilli were present in all mesothelial cells and were most concentrated in the ventral and caudal portions of the lung and parietal mediastinum. They were least concentrated on the ribs. Generally, more microvilli were present on the visceral side compared to the parietal side at the same part of the chest, and more on the caudal than on the cranial portions on either side of the pleural cavity. The number of microvilli on the mesothelial cells probably reflected individual cellular activities, such as fluid absorption. Microvilli, by holding conglomerated mucopolysaccharide, may also have acted as a buffer zone to decrease the friction between the lung and the chest wall. Mesothelial cells in the Kampmeier foci, where macrophages and foreign particles accumulated, appeared to have quantitatively incr...