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Renal outer medullary oxidative stress is dependent upon elevated renal perfusion pressure in angiotensin II‐induced hypertensive rats
Author(s) -
Polichnowski Aaron James,
Jin Chunhua,
Yang Chun,
Cowley Allen W.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.1016.6
Subject(s) - endocrinology , medicine , kidney , oxidative stress , angiotensin ii , chemistry , blood pressure , perfusion , renal circulation , nitric oxide synthase , nitric oxide , renal blood flow
Renal outer medullary (OM) injury in angiotensin II (AngII)‐infused rats is largely pressure dependent. We investigated the role of elevated renal perfusion pressure (RPP) versus circulating AngII on renal OM oxidative stress and nitric oxide synthase (NOS) activity in male Sprague Dawley rats. An aortic balloon occluder positioned between the renal arteries maintained RPP to the servocontrolled (SC) left kidney at baseline levels while the uncontrolled (UC) right kidney was exposed to elevated RPP during 14 days of AngII (25 ng/kg/min) infusion. RPP in UC kidneys was higher (p < 0.05) compared to SC kidneys and sham rats (170.3 ± .1, 117.3 ± .7, 115.8 ± .4 mmHg; respectively). OM superoxide production, determined using an oxy‐ethidium fluorescence assay, was higher (p<0.05) in UC vs. SC and sham kidneys (8149 ± 474, 7024 ± 472, 6465 ± 279 RFU, respectively). OM SOD activity (U/mL/ug protein) was unchanged in SC kidneys (2.3 ± .2), but was reduced (p<0.05) in UC vs. sham kidneys, (2.0 ± .2 vs. 2.7 ± .3, respectively). OM NOS activity (nmol cit/hr/mg protein) was increased (p<0.05) in UC (6.5 ± .7) and SC (7.0 ± .7) versus sham kidneys (4.3 ± .6). Elevated RPP tended (p=0.09) to lower OM NOS activity in UC vs. SC kidneys. In conclusion, elevated RPP stimulated excess OM superoxide production and tended to lower NOS activity in AngII‐induced hypertension, which can explain the significant pressure‐induced OM injury in this model.