The role of intravesical polymorphonuclear leukocytes in experimental cystitis.

Electron and light microscopic observations were made on experimentally induced cystitis in rats with particular emphasis on the role of polymorphs in the wall of the urinary bladder. Polymorphs appear from the time of invasion of bacteria to the epithelial cells of the bladder, aggregate primarily around infected epithelial cells, which become surrounded and isolated from healthy epithelial cells, and accelerate the desquamation of the infected epithelial cells. In the submucosal layer, all invading bacteria are phagocytized by polymorphs. Although polymorphs found in the intercellular space of the epithelial cells do not show phagocytosis, those that are released into the lumen of the urinary bladder do.