Envolvimento da pentraxina 3 (PTX3) na patogênese da cistite hemorrágica induzida por ifosfamida em camundongos

Abstract

The Hemorrhagic Cystitis (HC) is an inflammatory reaction usually associated with Cancer Chemotherapy with Oxazaphosphorines. It is an innate inflammatory response to vesical irritation by Acrolein, an hepatic metabolite of the treatment with Iphosphamide and Cyclophosphamide. The role of toll-like receptor (TLR) engagement and TNF-α and IL-1β expression and the involvement of iNOS and COX-2 in the pathogenesis has been well demonstrated in a murine model of HC. Recent data configure pentraxin 3 (PTX3) as an inflammatory mediator in several experimental models of innate immune response in vivo, with a straight relation with TLR engagement. Because of that, this study looks at the involvement of PTX3 in the pathogenesis of iphosphamide–induced HC in mice. For this purpose, the mRNA to PTX3 and IL-1β t was quantified by RT-PCR in groups of C57BL6 mice treated with Iphosphamide or Saline. After that, groups of transgenic and Knock-Out mice to PTX3 and its respectives wild-type controls were treated with Iphosphamide or saline with intention to measure the Bladder Wet Weight (BWW), histomorphometric scores and Immunohistochemistry and RT-PCR to PTX3, IL-1β, TNF-α e iNOS analysis. The transgenic mice and its controls were killed in 3h and 12h after the treatment, while the PTX3 KO and its controls were killed after 12 hours. Finally, the experimental HC was modulated by pretreatment with Talidomide, Pentoxiphiline, MESNA, Amifostine and Aminoguanidine and the bladders submitted to immunohistochemistry assay (PTX3, TNF-α, IL-1β and iNOS). By RT-PCR quantification, mRNA for PTX3 was expressed 70 times more in mice treated with iphosphamide than in controls, while IL-1β RNAm had an expression rate of 10 times. PTX3 transgenic mice had initial reduction of the inflammatory response with less expression of PTX3 and TNF-α and greater expression of iNOS. In the other hand, after 12 hours, the PTX3 transgenic mice had more inflammatory signs with superior expression of all the mediators. There was no difference between the PTX3 KO mice and its controls in the HC intensity although differences between groups were seen in cytokines expression. Talidomide and MESNA produced substantial reduction on the PTX3 expression, the same was seen to TNF-α, while the amifostine marked inhibition of HC had low effect on PTX3 expression. These data as a whole, point to an unequivocal involvement of PTX3 in the pathogenesis of innate inflammatory response of HC in mice with close relation with TNF-α engagement.