Antioxidant-rich diet relieves hypertension and reduces renal immune infiltration in spontaneously hypertensive rats.
Previous studies have demonstrated that oxidative stress contributes to hypertension and treatments with either antioxidant or immunosuppressive/anti-inflammatory agents improve hypertension in spontaneously hypertensive rats (SHR). The present study was performed to determine if the antihypertensive effects of an antioxidant-rich diet are associated with reduction in the renal immune infiltration. Rats were divided into experimental groups (n=5 each) that were followed 7 months after birth, during which they were fed either a regular or antioxidant-enriched (test) diet as follows: SHR-R group=regular diet; SHR-T group=test diet throughout the experiment; SHR-S group=test diet for 4 months switched to regular diet thereafter; WKY group=control rats given regular diet. The SHR-T rats showed a significant reduction in systolic blood pressure (mm Hg): SHR-T=179.6+/-12.9 versus SHR-R=207.5+/-9.6 (P<0.001) and plasma hydrogen peroxide concentration (SHR-T=15+/-4 micro mol/L versus 34+/-9 in SHR-R rats). This was accompanied by significant reductions of renal tissue nitrotyrosine abundance, tubulointerstitial infiltration (cells/mm(2)) of lymphocytes (SHR-T=18+/-3 versus SHR-R=30+/-4, P<0.001), macrophages (SHR-T= 17+/-3 versus SHR-R=22+/-3), and angiotensin II-positive cells (SHR-T= 17+/-2 versus SHR-R=25+/-5, P<0.01). Results in the SHR-S group were intermediate between the SHR-R and SHR-T groups. The intensity of the infiltration of lymphocytes, macrophages, and angiotensin II-positive cells significantly correlated with systolic blood pressure. Thus, the present study demonstrates that an antioxidant-enriched diet reduces the renal interstitial inflammation and improves hypertension in SHR. These findings point to interrelation between oxidative stress and inflammatory reactivity in the pathogenesis of hypertension.
Rodriguez-Iturbe
Bernardo
B
Renal Service and Laboratory, Hospital Universitario, Instituto de Investigaciones Biomédicas (Fundacite-Zulia), Universidad del Zulia, Maracaibo, Venezuela. bri@iamnet.com
Zhan
Chang-De
CD
Quiroz
Yasmir
Y
Sindhu
Ram K
RK
Vaziri
Nosratola D
ND
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage; D001794:Blood Pressure / Q000187:drug effects; D004032:Diet; D005260:Female; D006861:Hydrogen Peroxide / Q000097:blood; D006973:Hypertension / Q000097:blood / Q000503:physiopathology / Q000517:prevention & control*; D007668:Kidney / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D007678:Kidney Glomerulus / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008214:Lymphocytes / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D014810:Vitamin E / Q000008:administration & dosage
D000975:Antioxidants; D014810:Vitamin E; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D001205:Ascorbic Acid