Acute urinary bladder distension triggers ICAM-1-mediated renal oxidative injury via the norepinephrine-renin-angiotensin II system in rats.
OBJECTIVE
Acute urinary bladder distension (AUBD) can activate bladder mechanical afferent and renal sympathetic nerves, which contributes to renal vasoconstriction. We hypothesized that AUBD-induced renal sympathetic activation may contribute to inflammatory responses and end-organ damage via activation of angiotensin-II-receptor-mediated intercellular adhesion molecule-1 (ICAM-1) expression and leukocyte infiltration in the kidney.


METHODS
We evaluated the effect of 2 hours of AUBD induced by a threshold volume (micturition volume) on renal oxygen tension, microcirculation, renal reactive oxygen species (ROS) and monocyte/ macrophage (ED-1) infiltration, and ICAM-1 expression in the kidneys of urethane-anesthetized female Wistar rats. Bilateral ureteral dissection, renal denervation and intrarenal angiotensin II type 1 receptor blockade (2 mg/kg valsartan) were used to determine their roles in AUBD-induced renal oxidative stress.


RESULTS
Our results showed that AUBD evoked hypertension, a reduction in cortex oxygen tension and microcirculation, and increased renal ROS production, which were caused by increased perivascular and interstitial monocyte/macrophage infiltration and endothelial ICAM-1 overexpression. Renal denervation and angiotensin II type 1 receptor antagonist, but not bilateral ureter dissection, abolished the reduction in cortex oxygen tension and microcirculation, increased renal ROS production, increased perivascular monocyte/macrophage infiltration, and led to endothelial ICAM-1 overexpression in the kidney.


CONCLUSIONS
Acute urinary retention enhances renal sympathetic activity, which causes renal vasoconstriction and increases oxidative stress, adhesion-molecule expression and leukocyte infiltration in the rat kidney via the angiotensin II type 1 receptor pathway.
Chen
Show-Shing
SS
Department of Surgery, Kuang-Tien General Hospital, Taichung, Taiwan.
Chen
Wang-Chuan
WC
Hayakawa
Satoshi
S
Li
Ping-Chia
PC
Chien
Chiang-Ting
CT
D000208:Acute Disease; D000804:Angiotensin II / Q000502:physiology; D000818:Animals; D005260:Female; D018799:Intercellular Adhesion Molecule-1 / Q000502:physiology*; D007668:Kidney / Q000294:innervation / Q000378:metabolism*; D009638:Norepinephrine / Q000502:physiology*; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D012084:Renin-Angiotensin System / Q000502:physiology*; D001743:Urinary Bladder / Q000503:physiopathology*
D000804:Angiotensin II; D018799:Intercellular Adhesion Molecule-1; D009638:Norepinephrine