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Protective effects of hydrogen sulfide pretreatment on cyclophosphamide-induced bladder dysfunction in rats via suppression of bladder afferent nerves

Cyclophosphamide (CYP), a broad-spectrum anticancer drug, causes serious side effects, such as haemorrhagic cystitis (HC). Hydrogen sulfide (H₂S), an endogenous gasotransmitter, has physiological properties, including anti-inflammation, anti-oxidation, and neuromodulation. In this study, we investigated the effects of NaHS (H₂S donor) pretreatment on bladder dysfunction in CYP-treated rats. Male Wistar rats were intraperitoneally pretreated with NaHS (3 or 10 μmol/kg) or vehicle once daily for 7 days before cystometry, and CYP (150 mg/kg) or saline was intraperitoneally administered 2 days before cystometry. After cystometry, the bladder tissues were collected for haematoxylin and eosin staining. In some rats, capsaicin (CAP), which can desensitise CAP-sensitive afferent nerves, was subcutaneously injected at 125 mg/kg 4 days before cystometry. CYP reduced intercontraction intervals (ICI) and bladder compliance (Comp) and increased the number of non-voiding contractions (NVCs) compared with the saline-treated control group. NaHS pretreatment dose-dependently improved the CYP-induced these changes. In bladder tissues, CYP increased histological scores of neutrophil infiltration, haemorrhage, and oedema, while NaHS had no effect on these CYP-induced changes. CAP showed a tendency to suppress CYP-induced changes in ICI. NaHS-induced improvement in CYP-induced changes in urodynamic parameters were not detected in CAP-treated rats. These findings suggest that NaHS pretreatment prevented bladder dysfunction in CYP-treated rats by suppressing CAP-sensitive bladder afferent nerves, but not by suppressing bladder inflammation. Therefore, H₂S represents a new candidate as a protective drug for bladder dysfunction induced by HC, a side effect of CYP chemotherapy.