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Pressure‐induced renal injury is attenuated in norepinephrine‐induced hypertensive rats
Author(s) -
Polichnowski Aaron James,
Kaldunski Mary,
Cowley Allen W
Publication year - 2008
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.22.1_supplement.969.10
Subject(s) - medicine , kidney , saline , infiltration (hvac) , masson's trichrome stain , necrosis , fibrosis , perfusion , endocrinology , balloon catheter , blood pressure , pathology , urology , balloon , physics , thermodynamics
We investigated the role of elevated renal perfusion pressure (RPP) versus circulating norepinephrine (NE) on renal outer medullary (OM) injury in Sprague Dawley rats. Rats were prepared with carotid and femoral arterial catheters, a femoral venous catheter, and a servo‐controlled aortic balloon occluder positioned between the renal arteries. Rats were infused with NE (0.5, 1, and 2 ug/kg/min on Days 1, 2, and 3–14, respectively) for 14 days while sham rats received saline. On day 14 of infusion, kidneys were removed and prepared for histological analysis. Sections were stained with Gomori trichrome to identify tubular necrosis, and immunostained with antibodies for α‐SMA for fibrotic tissue and for ED‐1 positive cells for macrophage infiltration. Over the period of NE or saline infusion, RPP of the uncontrolled kidney (149.1 ± 4.2 mmHg) was significantly higher (p < .05) versus the controlled (117.1 ± 0.4 mmHg) and sham (110.7 ± 0.4 mmHg) kidneys. The uncontrolled, controlled, and sham kidneys had similar levels of tubular necrosis (0.4 ± .17, .04 ± .02, and .01 ± .01 %, respectively), OM fibrosis (1 ± .19, 0.9 ± .19, and 1.4 ± .28 %), and macrophage infiltration (35.2 ± 7.9, 27.2 ± 7.3, and 21.0 ± 1.6). In conclusion, neither elevated RPP nor NE results in significant OM renal injury in NE‐induced hypertension. This is in contrast to AngII‐induced hypertension, in which OM renal injury is largely pressure dependent.