Gastric damage induced by different doses of indomethacin in rats is variably affected by inhibiting iNOS or leukocyte infiltration.

AIM: To evaluate the effect of inhibiting inducible nitric oxide synthase (iNOS), by aminoguanidine, or leukocyte infiltration, by fucoidin, on gastropathy induced by two different doses of indomethacin in rats. METHODS: Rats were treated with saline, aminoguanidine (50 or 100 mg.kg(-1), i. p.) or fucoidin (25 mg.kg(-1), i. v.). Indomethacin was then given at a dose of 5 or 20 mg.kg(-1). At the end of 3 h, macroscopic gastric damage and myeloperoxidase (MPO) activity were assessed. RESULTS: Aminoguanidine reduced the gastric damage induced by indomethacin at 20 mg.kg(-1), but increased gastric MPO activity. However, aminoguanidine did not influence the gastric damage induced by indomethacin at 5 mg.kg(-1). Fucoidin prevented both the gastric damage and the increase in gastric MPO activity induced by indomethacin at 20 mg. kg(-1), but not at 5 mg.kg(-1). CONCLUSION: Indomethacin at a dose of 20 mg.kg(-1), but not at 5 mg.kg(-1), induced gastropathy dependent on neutrophil infiltration and iNOS-generated NO.

Amifostine and glutathione prevent ifosfamide- and acrolein-induced hemorrhagic cystitis.

INTRODUCTION: Ifosfamide (IFS) is an antineoplastic alkylating agent whose major side effect is hemorrhagic cystitis (HC). This toxicity is attributed to the renal excretion of acrolein (ACR), a highly urotoxic IFS metabolite. Despite the clinical use of mesna to prevent HC, a significant percent ( approximately 33%) of patients present with at last one feature of HC, mainly hematuria. AIM: To investigate the use of two antioxidants-amifostine and glutathione-for the prevention of experimental IFS- and ACR-induced HC. MATERIALS AND METHODS: Male Swiss mice were treated intraperitoneal (i.p.) with saline (control), glutathione (125, 250 or 500 mg/kg) or amifostine (25, 50 or 100 mg/kg), and 30 min later they received a single i.p. injection of IFS at a dose of 400 mg/kg. To investigate the systemic effects of the antioxidants on ACR-induced HC, the animals were treated with saline, amifostine (50 mg/kg, i.p.) or glutathione (500 mg/kg, i.p.), and 30 min afterward with 75 mug ACR intravesically (i.ve.). In another set of experiments, the antioxidants were injected directly into the bladder, where the mice received a single i.ve injection of ACR (75 mug) plus amifostine (1.5 mg/kg) or glutathione (2 mg/kg). HC was measured 3 h after IFS or ACR injection according to bladder wet weight, macroscopic (edema and hemorrhage) and microscopic changes, i.e., edema, hemorrhage, cellular infiltration, fibrin deposition and urothelial desquamation. RESULTS: Pretreatments with amifostine or glutathione prevented IFS-induced HC in a dose-dependent manner. Furthermore, ACR-induced HC was also prevented by systemic (i.p.) or local (i.ve.) pretreatment with glutathione or amifostine. The greatest protective effect was seen with local amifostine treatment (2 mg/kg i.ve.) (P < 0.05). CONCLUSIONS: Glutathione and amifostine show a beneficial effect in experimental IFS- and ACR-induced HC. Thus, they should be investigated as an alternative treatment to prevent HC observed in patients undergoing IFS treatment.