MP24-11 THE INCREASED EXPRESSION OF TRANSIENT RECEPTOR POTENTIAL VANILLOID-4 (TRPV4) IN CYCLOPHOSPHAMIDE-INDUCED INFLAMMATORY CYSTITIS

Abstract

inoculation of uropathogenic E. coli strain UTI89. The extent of neutrophil infiltration in the urothelium was assessed using confocal immunofluorescence microscopy (CIM) and urine neutrophil elastase activity assay. The presence of intracellular bacterial community (IBC) formed by UTI89 was assessed at 12 hours, 24 hours, 3 days and 7 days post-UTI89 inoculation with CIM using an anti-E. coli antibody and bacterial culture. Functional defects in neutrophil migration were verified using in vitro migration assays of peripheral blood neutrophils. RESULTS: Hyperglycemia (440-470 mg/dl) was induced reproducibly and permanently in all the mice administered with STZ with little inter-animal variation. Normal controls and STZ-induced DM mice transurethrally inoculated with UTI89 showed marked differences in neutrophil infiltration at all time points examined. While in normal mice neutrophils that infiltrated into the urothelium were most frequently seen surrounding IBCs, in STZ mice the neutrophils were very sparse and scattered. There was a 2-fold reduction of neutrophil elastase at 12 hours post-inoculation in STZ mice than in the normal controls. In contrast, IBCs were considerably more prevalent in STZ mice at 12 and 24 hours post-inoculation. On day 3 and 7 when few IBCs remained in normal mouse urothelium, numerous IBCs were seen in the STZ mice, often lining the entire segment of superficial urothelium. Bacterial culture confirmed the IBC staining data. Finally, in vitro assay showed that neutrophils from the STZ mice were three-fold less migratory than those from the normal mice. CONCLUSIONS: Our data provide the first experimental evidence indicating that diabetic conditions impair neutrophil migration and infiltration into the urothelium, resulting in markedly delayed host responses in IBC clearance and consequently prolonged bladder infection.