Expressions of uroplakins in the mouse urinary bladder with cyclophosphamide-induced cystitis

Even though uroplakins (UPs) are believed to serve a strong protective barrier against toxic materials, cyclophosphamide (CP) causes extensive cystitis. We investigated the expression of UPs in the urothelium in CP induced mouse cystitis. A total of 27 ICR female mice received a single intraperitoneal injection of 200 mg CP/kg. Nine CP-treated mice and 6 controls were sequentially killed at 12, 24, and 72 hr post injection. Extensive cystitis and an increased vesical weight were seen. These all peaked within 12 hr post injection and they tended to decrease thereafter. The level of all the UPs mRNA, the protein expressions of UP II and III on immunoblotting study, and the expression of UP III on immunolocalization study were maximally suppressed within 12 hr; this partially recovered at 24 hr, and this completely recovered at 72 hr post CP injection. In conclusion, CP reduced the expression of UPs. The reduction of the UPs mRNA and protein was time dependent, and this peaked within 12 hr after CP injection. However, the damage was rapidly repaired within 24 hr. This study demonstrates a dynamic process, an extensive reduction and rapid recovery, for the UPs expression of the mouse urinary bladder after CP injection.