Aging increases oxidative stress and renal expression of oxidant and antioxidant enzymes that are associated with an increased trend in systolic blood pressure.
The aim of this study was to investigate whether the effects of aging on oxidative stress markers and expression of major oxidant and antioxidant enzymes associate with impairment of renal function and increases in blood pressure. To explore this, we determined age-associated changes in lipid peroxidation (urinary malondialdehyde), plasma and urinary hydrogen peroxide (H(2)O(2)) levels, as well as renal H(2)O(2) production, and the expression of oxidant and antioxidant enzymes in young (13 weeks) and old (52 weeks) male Wistar Kyoto (WKY) rats. Urinary lipid peroxidation levels and H(2)O(2) production by the renal cortex and medulla of old rats were higher than their young counterparts. This was accompanied by overexpression of NADPH oxidase components Nox4 and p22(phox) in the renal cortex of old rats. Similarly, expression of superoxide dismutase (SOD) isoforms 2 and 3 and catalase were increased in the renal cortex from old rats. Renal function parameters (creatinine clearance and fractional excretion of sodium), diastolic blood pressure and heart rate were not affected by aging, although slight increases in systolic blood pressure were observed during this 52-week period. It is concluded that overexpression of renal Nox4 and p22(phox) and the increases in renal H(2)O(2) levels in aged WKY does not associate with renal functional impairment or marked increases in blood pressure. It is hypothesized that lack of oxidative stress-associated effects in aged WKY rats may result from increases in antioxidant defenses that counteract the damaging effects of H(2)O(2).
Gomes
Pedro
P
Institute of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Portugal.
Simão
Sónia
S
Silva
Elisabete
E
Pinto
Vanda
V
Amaral
João S
JS
Afonso
Joana
J
Serrão
Maria Paula
MP
Pinho
Maria João
MJ
Soares-da-Silva
Patrício
P
D000375:Aging; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001794:Blood Pressure / Q000502:physiology*; D002374:Catalase / Q000378:metabolism; D006339:Heart Rate; D006861:Hydrogen Peroxide / Q000097:blood / Q000378:metabolism / Q000652:urine; D007672:Kidney Cortex / Q000201:enzymology / Q000378:metabolism*; D015227:Lipid Peroxidation; D008297:Male; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism; D016877:Oxidants / Q000378:metabolism*; D018384:Oxidative Stress; D051381:Rats; D011921:Rats, Inbred WKY; D013482:Superoxide Dismutase / Q000378:metabolism; D000099156:Superoxide Dismutase 2
D000975:Antioxidants; D002374:Catalase; D006861:Hydrogen Peroxide; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; D016877:Oxidants; D013482:Superoxide Dismutase; D000099156:Superoxide Dismutase 2; C499089:Sod3 protein, rat; C498911:Nox4 protein, rat; C515768:Cyba protein, rat