Contribution of flavonoid antioxidants to the preventive effect of mesna in cyclophosphamide-induced cystitis in rats.

Cyclophosphamide (CP) is widely used, alone or in combination with other chemotherapeutic agents, for treatment of neoplastic diseases. Its urotoxicity may cause dose-limiting side-effects, for example hemorrhagic cystitis. The agent most often used to prevent this side-effect is mesna (2-mercaptoethane sulfonate). Overproduction of reactive oxygen species during inflammation is one reason for possible urothelial injury. The aim of this study was to evaluate whether combinations of quercetin and epigallocatechin 3-gallate (EGCG), flavonoid antioxidants and mesna could prevent cystitis induced by cyclophosphamide, better than mesna alone. A total of 38 male Sprague-Dawley rats were divided into five groups. Four groups received single dose of CP (100 mg kg(-1)) intraperitoneally at the same time. Group 2 received CP only, group 3 received mesna (3 x 21.5 mg kg(-1)), group 4 received a single dose of mesna+EGCG (2 x 20 mg kg(-1)), and group 5 received a single dose of mesna+quercetin (2 x 20 mg kg(-1)), before and after CP injection. Group 1 (not treated) served as control. CP injection alone resulted in severe cystitis. Mesna resulted in some, but not full, protection against CP toxicity. Quercetin and catechine, together with mesna, resulted in full protection against CP toxicity, on the basis of histopathology of the urinary bladder. It was concluded that oxidants might be important in the pathogenesis of CP-induced cystitis, and that flavonoid antioxidants, used in addition to mesna, may help to ameliorate bladder damage.