Salutary effects of a novel oxidative stress modulator on adenine-induced chronic progressive tubulointerstitial nephropathy.

BACKGROUND: Oxidative stress and inflammation promote the development and progression of chronic kidney disease. Oxidative stress is associated with depletion of tissue glutathione (GSH), the most abundant endogenous intracellular antioxidant, but degradation of oral GSH by digestive enzymes limits its therapeutic use. We hypothesized that GSH repletion with F1, a novel oral GSH precursor containing cystine as a cysteine carrier, would restore tissue GSH and attenuate oxidative stress and inflammation, and thereby reduce the severity of interstitial nephropathy in chronic renal failure (CRF).
METHODS: Male Sprague-Dawley rats (n=5-8) were assigned to 3 groups: Control (regular rat chow), CRF (rat chow containing 0.7% adenine), and F1-treated CRF (rat chow containing 0.7% adenine and F1, 0.5g/kg/day) for 2-weeks. Animals were switched to regular chow and euthanized after 2 additional weeks.
RESULTS: Consumption of 0.7% adenine-containing diet caused azotemia; severe kidney swelling; heavy tubular and glomerular damage; massive tubulointerstitial nephropathy; impaired urinary concentrating capacity; severe anemia; increased markers of oxidative stress, plasma oxidized glutathione disulfide (GSSG); reduced GSH/GSSG ratio and manganese superoxide dismutase; increased expression of inflammatory mediators (cyclooxygenase-2, cytoplasmic NF-κB, p-IκBα, nuclear NF-κB p65), and 3-nitrotyrosine, p<0.05. Co-treatment with F1 significantly attenuated tubulointerstitial inflammation and edema, improved urinary concentrating capacity, azotemia and anemia, and normalized markers of tissue oxidative and nitrosative stress, p<0.05.
CONCLUSIONS: The novel oxidative stress modulator, F1, markedly attenuated oxidative stress indicators, inflammation, renal injury and dysfunction in the rat model of CRF. Studies to determine the effects of F1 in other models of acute and CRF are warranted.