Efeito protetor da interleucina- 4 na cistite hemorrágica induzida por ifosfamida em camundongos

Abstract

Hemorrhagic cystitis (HC) is a limiting side effect from the clinic use of chemotherapy agents, mainly cyclophosphamide (CYP) and ifosfamide (IFS). This is due to the fact that acrolein is a urinary metabolite of CYP and IFS, which has been demonstrated to be the causative agent of hemorrhagic cystitis (HC) induced by these compounds. Based on previous experimental studies, most of them from the Laboratory of Pharmacology of Inflammation and Cancer of Federal University of Ceará, it was demonstrated the participation of inflammatory cytokines such as TNF-α, IL-1β, and the expression of iNOS and COX-2 in ifosfamide-induced HC. Thus, knowing that interleukin-4 (IL- 4) is an anti-inflammatory cytokine able to prevent the production of TNF-α, IL-1β, and decrease the expression of inflammatory enzymes such as iNOS and COX-2, we investigated whether IL- 4 is capable of reducing inflammatory changes seen with ifosfamide-induced HC. For this, male Swiss mice (25-30 g; 6 per group) were treated with saline or ifosfamide (400 mg/kg, intraperitoneally (ip) and analyzed by changes in bladder wet weight (BWW), macroscopic and microscopic parameters, exudate, and hemoglobin quantification. In other groups, IL- 4 (0,4; 2 or 10 ng) was administered ip 1h before ifosfamide administration. In other experimental groups, C57BL/6 WT (wild type) and C57BL/6 WT IL- 4 (-/-) knockout animals were treated with ifosfamide and analyzed for changes in BWW. Immunohistochemistry to TNF-α and IL-1β as well as protein identification by Western blot assay for iNOS and COX-2 were carried out on ifosfamide and IL- 4 treated animals. In other experimental groups, anti-IL- 4 serum was given (50 µL/animal, ip) 30 min before ifosfamide. In IL- 4 treated animals, BWW change was significantly less in animals treated with ifosfamide administration only, being reduced by 27% and 39% (2 and 10 ng respectively). Vascular permeability was reduced by 29% and 24%, and hemorrhage by 47% and 61% in those animals treated with IL- 4 (2 and 10 ng respectively). Exogenous IL- 4 also attenuated TNF-α, IL-1 β, iNOS and COX-2 expression on ifosfamide treated bladders. Moreover, knockout animals for IL- 4 (-/-) and animals treated with anti-IL- 4 serum exhibit a more severe degree of inflammation when compared to the wild type mice (approximately 44% and 28% respectively). IL- 4, an anti-inflammatory cytokine, can attenuate the inflammation seen with ifosfamide-induced hemorrhagic cystitis.