Hyperbaric oxygen treatment for experimental cyclophosphamide-induced hemorrhagic cystitis

Acrolein is a toxic metabolite of cyclophosphamide that causes hemorrhagic cystitis in 2 to 40% of treated patients. Hyperbaric oxygen (HBO) is used to treat poorly healing wounds in conditions such as Fournier's gangrene and radiation-induced cystitis. The present study was designed to evaluate the effects of HBO on acute acrolein-induced hemorrhagic cystitis in a rat model. Rats were divided into 4 groups. Group I served as a control and received only HBO prior to sacrifice. Group II received acrolein only, while groups III and IV received acrolein as well as HBO therapy. Hyperbaric oxygen (100% oxygen, 2.8 atmospheres, 90 minutes) was delivered twice a day for 4 days, with group III receiving a fifth HBO treatment just before acrolein and group IV receiving the fifth HBO treatment just after acrolein. After therapy, the amount of urothelial injury was determined morphometrically. Group II untreated rat bladders had only 33% of the urothelium intact after acrolein injury, whereas groups III and IV rat bladders had 93% (p < 0.01) and 55% (p < 0.01) intact urothelium, respectively, after treatment with HBO. The timing of the HBO treatment appeared to be a critical factor, with less injury occurring if the fifth HBO treatment immediately preceded acrolein. These results suggest that HBO may be useful as prophylaxis and treatment of cyclophosphamide-induced hemorrhagic cystitis.