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Elevated Arterial Perfusion Pressure Increases H2O2 in the Renal Medullary Interstitium
Author(s) -
Hu Chunyan,
Polichnowski Aaron,
Kurth Terry,
Mori Takefumi,
Ito Sadayoshi,
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.1160.3
Subject(s) - renal medulla , kidney , perfusion , medullary cavity , chemistry , renal artery , medulla , blood pressure , medicine , excretion , endocrinology , anatomy , urology
We established a direct role of arterial renal perfusion pressure (RPP) in renal injury using servo‐controlled techniques to maintain the left kidney of Sprague Dawley (SD) rats at normal RPP while exposing the right kidney to a high RPP during the development of hypertension (Hypertension 43: 752, 2004). These results showed that pressure‐induced renal injury was associated with activation of NF‐kβ and TGF–β1 in the renal outer medulla indicating oxidative stress was involved in these mechanically‐induced responses. In the present study, we determined whether medullary interstitial [H 2 O 2 ], a reactive oxygen species, could be induced by a rapid increase in RPP. Left kidneys of SD rats were denervated, a linear microdialysis fiber implanted in the outer medulla, a ureteral catheter inserted, and an adjustable occluder placed around the aorta proximal and distal to the renal arteries to raise and lower RPP. Following 60 min. equilibration, dialysate was collected (2 μl/min) for 30 min and H 2 O 2 measured at three levels of RPP (Amplex Red). As RPP was increased from 73±1 to 93±1 mmHg, medullary H 2 O 2 was relatively constant (650±62 to 733±89 nM) but when RPP increased to 138±3, H 2 O 2 levels increased to 1237±78 nM (P<0.05) with parallel increases in urinary H 2 O 2 excretion. We conclude that elevations of RPP >100 mmHg rapidly and markedly increase the levels of H 2 O 2 within the renal medulla. (Support: HL‐29587)