N-acetylcysteine alleviates angiotensin II-mediated renal fibrosis in mouse obstructed kidneys

Abstract

Aim: To investigate the effects of ROS scavenger N-acetylcysteine (NAC) on angiotensin II (Ang II)-mediated renal fibrosis in vivo and in vitro. Methods: Mice were subjected to unilateral ureteral obstruction (UUO), and then treated with vehicle or NAC (250 mg/kg, ip) for 7 days. Histological changes of the obstructed kidneys were observed with Masson's trichrome staining. ROS levels were detected with DHE staining. The expression of relevant proteins in the obstructed kidneys was assessed using Western blotting assays. Cultured rat renal fibroblast NRK-49F cells were used for in vitro experiments. Results: In the obstructed kidneys, Ang II levels were significantly elevated, and collagen I was accumulated in the interstitial spaces. Furthermore, ROS production and the expression of p47 (a key subunit of NADPH oxidase complexes) were increased in a timedependent manner; the expression of fibronectin, α-SMA and TGF-β were upregulated. Administration of NAC significantly alleviated the fibrotic responses in the obstructed kidneys. In cultured NRK-49F cells, treatment with Ang II (0.001-10 μmol/L) increased the expression of fibronectin, collagen I, α-SMA and TGF-β in dose-dependent and time-dependent manners. Ang II also increased ROS production and the phosphorylation of Smad3. Pretreatment with NAC (5 μmol/L) blocked Ang II-induced oxidative stress and ECM production in the cells. Conclusion: In mouse obstructed kidneys, the fibrotic responses result from Ang II upregulation can be alleviated by the ROS scavenger N-acetylcysteine.

N-acetylcysteine ameliorates contrast‑induced kidney injury in rats with unilateral hydronephrosis

“…Three weeks after obstruction relief, UUO+iohexol+NAC rats had lower apoptosis rate, lower Bax mRNA expression, higher expression of Bcl-2 mRNA, and higher ratio of Bcl-2/Bax when compared with day 1 after drug administration. Only one previous study showed a role of NAC in preventing renal impairment in a model of kidney obstruction ( 18 ), but the animal model was different from the present study, which used rats instead of mice. In addition, the study by Shen et al ( 18 ) focused on the protective effect of NAC on renal fibrosis, while the present study focused on the protective role of NAC on the apoptosis of renal cells.…”

“…Only one previous study showed a role of NAC in preventing renal impairment in a model of kidney obstruction ( 18 ), but the animal model was different from the present study, which used rats instead of mice. In addition, the study by Shen et al ( 18 ) focused on the protective effect of NAC on renal fibrosis, while the present study focused on the protective role of NAC on the apoptosis of renal cells. Therefore, we explored different mechanisms of the protective effects of NAC.…”

Mitochondrial dysfunction and endoplasmic reticulum stress in the promotion of fibrosis in obstructive nephropathy induced by unilateral ureteral obstruction

“…25,33,49,51,67 Although progression of fibrosis involves several signaling pathways, the current information on the UUO model seems to suggest that preserving mitochondrial and ER function, especially the processes related to FA β-oxidation, can prevent, or at least delay, the fibrotic processes and loss of renal function. 7,23,33,51,98,120,122,123 Therefore, the steps that follow must involve not only a deeper description of the mechanisms involved in mitochondrial alterations and their pathological crosstalk with the ER, but also the temporal analysis of them. This is with the aim of developing more targeted mitochondrial therapies for future use in the clinic to treat obstructive nephropathy in patients.…”

Influência da sobrecarga de sódio em ratos submetidos à isquemia e reperfusão renal: tratamento com N-acetilcisteína

“…NAC é caracterizado por ter um grupamento tiol em sua estrutura molecular e o aminoácido cisteína o torna capaz de aumentar a produção da glutationa (Bernard el at.,1984;Smillstein et al,1988). Estudos em camundongos C57BL/J6 submetidos à uninefrectomia direita e obstrução ureteral tratados ou não com NAC mostraram que a obstrução e uninefrectomia causaram a ativação do SRAA renal, aumentando a produção de H2O2, porém, o tratamento com NAC diminuiu colágeno, TGF-β, α-actina, mostrando assim uma capacidade antifibrótica e anti-inflamatória da NAC (Shen et al, 2016 anti-inflamatório e de proteção renal (Moreira et al, 2016).…”

“…Outra possível via da diminuição da pressão arterial seria através do SRAA já que foi observado que a infusão de NAC (5mmol/kg/hr) preveniu o aumento da pressão arterial em ratos inconscientes, e diminuiu também a ANG II plasmática o que indicaria efeitos diretos sobre a ação do SRAA por diminuir a atividade da ECA (Boesgaard et al, 2003). Já em ratos que passaram por obstrução ureteral, NAC mostrou resultados positivos ao diminuir a fibrose relacionada a ativação do SRAA via ANG II (Shen et al,2016) No presente estudo, ao analisarmos a expressão gênica de renina (Figura 40), notamos que a dieta hipersódica diminuiu esta expressão nos grupos SHAM HR e I/R HR, este resultado é esperando já que é bem estabelecido na literatura que altas concentrações de sal diminuem a ativação do SRAA (Guyton e Hall, 2006;Ferreira et al, 2010;Katayama et al, 2014), NAC como agente protetor renal fora previamente descrito em diversos estudos, promovendo aumento da proteína e gene klotho (Shimizu et al, 2012;Shimizu et al, 2016), diminuindo a fibrose intersticial, dilatação tubular e necrose tubular (Moreira et al,2016). Os achados do presente trabalho são promissores, NAC foi capaz de prevenir o desenvolvimento de albuminúria nos animais com a isquemia e reperfusão associada a uma dieta hipersódica (Figura 30), indicando que atua como protetor da barreira de filtração glomerular.…”