Involvement of nitric oxide in microcirculatory reactions after ischemia-reperfusion of the rat urinary bladder.
BACKGROUND
Nitric oxide (NO) plays a role in inflammation. Our aim was to investigate the role of NO in the microcirculatory changes after ischemia-reperfusion (I/R) of the bladder using intravital videomicroscopy (IVM).


METHODS
In rats, 60 min of bladder ischemia followed by 30 min of reperfusion was performed in the presence of N(G)-nitro-L-arginine methyl ester (L-NAME), the NO precursor L-arginine, or saline pre-treatments. Venular red blood cell velocity (RBCV), functional capillary density (FCD), vessel diameters, and leukocyte-endothelial cell interactions in postcapillary venules were determined. Concentrations of nitrite/nitrate in the plasma and myeloperoxidase (MPO) levels in the lungs and the bladder were measured.


RESULTS
Elevations of the numbers of rolling and adherent leukocytes, and of plasma nitrite/nitrate levels were found, while FCD and RBCV decreased. L-NAME pretreatment ameliorated the enhanced leukocyte-endothelial cell interactions without influencing the microcirculatory perfusion. In contrast, the L-arginine pretreatment further increased plasma nitrite/nitrate levels and preserved the FCD and RBCV, but did not affect leukocyte-endothelial interactions. None of these treatments influenced MPO activities.


CONCLUSIONS
Our results suggest that NO plays an enhancing role in the I/R-induced neutrophil-endothelial interactions of the bladder. Supplementation of NO ameliorates the microcirculatory perfusion deficit without influencing the postischemic microcirculatory inflammatory reactions.
Bajory
Z
Z
Institute for Surgical Research, University of Munich, Munich, Germany. bajory@freemail.hu
Szabó
A
A
Király
I
I
Pajor
L
L
Messmer
K
K
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D001783:Blood Flow Velocity; D042783:Endothelial Cells / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects / Q000502:physiology; D036904:Leukocyte Rolling / Q000187:drug effects / Q000502:physiology; D008297:Male; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology; D018715:Microscopy, Video; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000503:physiopathology*; D001743:Urinary Bladder / Q000098:blood supply* / Q000293:injuries*
D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester