MODERATE STRESS PROTECTS FEMALE MICE AGAINST BACTERIAL-INFECTION OF THE BLADDER BY ELICITING UROEPITHELIAL SHEDDING

We have previously shown (M. Aronson, O. Medalia, D. Amichay, and O. N ativ, Infect. Immun. 56:1615-1617, 1988) that shedding of viable uroep ithelial cells (elicited by invading microorganisms) constitutes an an timicrobial defense mechanism. The present study deals with two differ ent stress-involving procedures, in which increased uroepithelial shed ding rendered female mice resistant to vesical infection. Moderate str ess was induced in female mice by exposing the animals either to const ant illumination for 96 h or to 37 degrees C heat for 24 h. In both ea ses, the fate of infection was considerably reduced as a result of inc reased epithelial shedding (P < 0.0001). Stress was manifested by both reduced thymic weight and increased blood corticosterone levels, Shed ding was also elicited by intraperitoneal injection of norepinephrine together with hydrocortisone or by intravesical injection of corticost erone. Constant illumination as well as heat enormously facilitated th e migration of polymorphonuclear cells into the bladder following the action of chemotactic stimuli. Male mice subjected to identical stress -generating conditions did not display considerable epithelial sheddin g or increased migration of polymorphonuclear cells, and they were nut protected from intravesical infection.