In human immunosuppression that occurs in uremic patients is associated with dysfunction of uremic toxins caused by neutrophils. The effect of uremic toxin p-cresol on the function of human neutrophils have been extensively investigated. This toxin is not properly filtered during hemodialysis and its accumulation in the blood promotes the inhibition of neutrophil oxidative metabolism, thus affecting its bactericidal function. The neutrophil dysfunction in nephropathic dogs has not been adequately investigated. Our group recently obtained evidence that the in vitro neutrophil oxidative metabolism of healthy dogs is affected when incubated as uremic serum, but to date no studies on the specific effect of p-cresol on neutrophil function in this species. In this sense, the present study aims to measure plasma concentrations of p-cresol in dogs with CRF and test the hypothesis that similarly to what happens in humans toxinaa this increase is associated with changes in oxidative metabolism and apoptosis of neutrophils. This will be a standardized methodology for measuring liquid-chromatographic plasma concentrations of this toxin in dogs healthy controls and patients with CRF equivalent to stage IV. It will also be evaluated and compared in vitro the specific effect of p-cresol on superoxide production, lipid peroxidation, and apoptosis rate of neutrophils isolated from dogs healthy controls, whereas plasma concentrations were observed "in vivo" in dogs with CRF . Cells isolated from 20 healthy dogs are incubated in RPMI medium with and without p-cresol, and plasma of dogs with CRF. The oxidative metabolism of neutrophils is evaluated by flow cytometry using the capillary tube hidroetidina. The viability and apoptosis of neutrophils is measured in capillary flow cytometry using Annexin V-PE system. Oxidative stress is assessed by quantification of plasma thiobarbituric reactive species, total antioxidant status, uric acid, total bilirubin and albumin.
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