TY - JOUR
T1 - The SOD Mimetic Tempol Ameliorates Glomerular Injury and Reduces Mitogen-Activated Protein Kinase Activity in Dahl Salt-Sensitive Rats
AU - Nishiyama, Akira
AU - Yoshizumi, Masanori
AU - Hitomi, Hirofumi
AU - Kagami, Shoji
AU - Kondo, Shuji
AU - Miyatake, Akira
AU - Fukunaga, Megumu
AU - Tamaki, Toshiaki
AU - Kiyomoto, Hideyasu
AU - Kohno, Masakazu
AU - Shokoji, Takatomi
AU - Kimura, Shoji
AU - Abe, Youichi
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2004/2
Y1 - 2004/2
N2 - It was shown recently that renal injury in Dahl salt-sensitive (DS) hypertensive rats is accompanied by mitogen-activated protein kinase (MAPK) activation. The present study was conducted to elucidate the contribution of reactive oxygen species to MAPK activities and renal injury in DS rats. DS rats were maintained on high salt (H; 8.0% NaCl; n = 7) or low salt (L; 0.3% NaCl; n = 6) diets; H + a superoxide dismutase mimetic, tempol (3 mmol/L in drinking water; n = 8); or H + hydralazine (0.5 mmol/L in drinking water; n = 8) for 4 wk. Mean BP (MBP) in DS/H and DS/L rats was 185 ± 7 and 113 ± 3 mmHg, respectively. DS/H rats showed a higher ratio of urinary protein excretion and creatinine (UproteinV/UcrV; 20.3 ± 1.1) and a higher cortical collagen content (22 ± 1 μg/mg) than in DS/L rats (2.4 ± 0.1 and 13 ± 1 μg/mg, respectively). The expression of p22-phox and Nox-1, essential components of NAD(P)H oxidase, in renal cortical tissue was approximately threefold higher in DS/H rats than in DS/L rats. Increased activities of renal cortical MAPK, including extracellular signal-regulated kinases (ERK) 1/ERK2 and c-Jun NH2-terminal kinases (JNK) were also observed in DS/H rats by 7.0 ± 0.7- and 4.3 ± 0.2-fold, respectively. Tempol treatment significantly decreased MBP (128 ± 3 mmHg), UproteinV/UcrV (4.8 ± 0.4), and cortical collagen content (14 ± 1 μg/mg) and normalized ERK1/ERK2 and JNK activities in DS/H rats. Histologically, tempol markedly ameliorated progressive sclerotic and proliferative glomerular changes in DS/H rats. Hydralazine-treated DS/H rats showed similar MBP (127 ± 5 mmHg) to tempol-treated DS/H rats. Hydralazine also decreased UproteinV/U crV (16.2 ± 1.5) and cortical collagen content (19 ± 1 μg/mg) in DS/H rats. However, these values were significantly higher than those of tempol-treated rats. Furthermore, although hydralazine significantly reduced JNK activity (-56 ± 3%), ERK1/ERK2 activities were unaffected. These data suggest that reactive oxygen species, generated by NAD(P)H oxidase, contribute to the progression of renal injury through ERK1/ERK2 activation in DS/H hypertensive rats.
AB - It was shown recently that renal injury in Dahl salt-sensitive (DS) hypertensive rats is accompanied by mitogen-activated protein kinase (MAPK) activation. The present study was conducted to elucidate the contribution of reactive oxygen species to MAPK activities and renal injury in DS rats. DS rats were maintained on high salt (H; 8.0% NaCl; n = 7) or low salt (L; 0.3% NaCl; n = 6) diets; H + a superoxide dismutase mimetic, tempol (3 mmol/L in drinking water; n = 8); or H + hydralazine (0.5 mmol/L in drinking water; n = 8) for 4 wk. Mean BP (MBP) in DS/H and DS/L rats was 185 ± 7 and 113 ± 3 mmHg, respectively. DS/H rats showed a higher ratio of urinary protein excretion and creatinine (UproteinV/UcrV; 20.3 ± 1.1) and a higher cortical collagen content (22 ± 1 μg/mg) than in DS/L rats (2.4 ± 0.1 and 13 ± 1 μg/mg, respectively). The expression of p22-phox and Nox-1, essential components of NAD(P)H oxidase, in renal cortical tissue was approximately threefold higher in DS/H rats than in DS/L rats. Increased activities of renal cortical MAPK, including extracellular signal-regulated kinases (ERK) 1/ERK2 and c-Jun NH2-terminal kinases (JNK) were also observed in DS/H rats by 7.0 ± 0.7- and 4.3 ± 0.2-fold, respectively. Tempol treatment significantly decreased MBP (128 ± 3 mmHg), UproteinV/UcrV (4.8 ± 0.4), and cortical collagen content (14 ± 1 μg/mg) and normalized ERK1/ERK2 and JNK activities in DS/H rats. Histologically, tempol markedly ameliorated progressive sclerotic and proliferative glomerular changes in DS/H rats. Hydralazine-treated DS/H rats showed similar MBP (127 ± 5 mmHg) to tempol-treated DS/H rats. Hydralazine also decreased UproteinV/U crV (16.2 ± 1.5) and cortical collagen content (19 ± 1 μg/mg) in DS/H rats. However, these values were significantly higher than those of tempol-treated rats. Furthermore, although hydralazine significantly reduced JNK activity (-56 ± 3%), ERK1/ERK2 activities were unaffected. These data suggest that reactive oxygen species, generated by NAD(P)H oxidase, contribute to the progression of renal injury through ERK1/ERK2 activation in DS/H hypertensive rats.
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U2 - 10.1097/01.ASN.0000108523.02100.E0
DO - 10.1097/01.ASN.0000108523.02100.E0
M3 - Article
C2 - 14747377
AN - SCOPUS:0942287120
VL - 15
SP - 306
EP - 315
JO - Journal of the American Society of Nephrology
JF - Journal of the American Society of Nephrology
SN - 1046-6673
IS - 2
ER -