Rat Models of Ascending Pyelonephritis due to Candida albicans

Publisher Summary This chapter presents two experimental rat models of ascending Candida pyelonephritis with combination pretreatments of leukopenia and vesicourethral reflux, and of unilaterally incomplete ureteral obstruction and VUR. Female Wistar rats weighing 200–250 g each are used in these models. The animals are allowed free access to standard laboratory chow and tap water. Candida albicans ATCC 10259 strain (serotype A) is used in this model. Candida cells grown for 48 hours at 37° C in Sabouraud's broth are harvested by centrifugation at 4° C for 10 minutes, washed twice with distilled water, and resuspended in sterile physiological saline. In the first model, the rats are rendered leukopenic by a single transperitoneal injection of 200 mg/kg body weight of cyclophosphamide, three days before inoculation of the Candida cells. Gentamicin (8 mg/kg) is administered once a day for one week following the administration of cyclophosphamide to prevent contaminating bacterial infections. Kidney histology is normally used to monitor the progress of infection. Within three days of inoculation, microcopy reveals acute pyelonephritis showing polymorphonuclear leukocyte infiltration, mucosal edema, and bleeding, together with Candida cells invading from the renal fornix in about half of the infected kidneys. In the second model, a midline incision is made at the lower abdomen after the skin is shaved with an electric clipper and then disinfected with an iodine-based solution. To produce open hydronephrosis, incomplete occlusion of the left ureter is induced by exposing and detaching the left ureter and applying a drop of an instant adhesive to the inferior end of the ureter.