Effect of inhibition of neuronal nitric oxide synthase and L-arginine supplementation on renal ischaemia-reperfusion injury and the renal nitric oxide system.
The role of nitric oxide synthases (NOS) and the nitric oxide (NO) substrate l-arginine in renal ischaemia-reperfusion (I/R) has been studied extensively. However, the results reported are often controversial. In the present study, we examined the effects of the neuronal (n) NOS inhibitor 7-nitroindazole (7-NI) and L-arginine administration on renal I/R injury and the renal NO system in rats. Following 7 days pretreatment with 7-NI (50 mg/kg per day), L-arginine (2 g/kg per day) or vehicle (dimethylsulphoxide : sesame oil, 1 : 9), the left renal vascular pedicles were clamped for 50 min in male Sprague-Dawley rats and kidneys were removed 24 h after reperfusion (n = 7/group). Neither 7-NI nor L-arginine had any effect on parameters of renal function, the grade of tissue injury or the number of terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL)-positive tubular cells compared with vehicle-treated rats. 7-Nitroindazole decreased nNOS mRNA expression and inducible (i) NOS protein levels, but had no effect on endothelial NOS expression. L-arginine supplementation increased mRNA expression of all NOS isoforms, but only increased protein expression of iNOS. The results of the present study demonstrate that selective inhibition of nNOS has no effect on renal injury, indicating that nNOS does not play a central role in the pathophysiology of renal I/R. In addition, although L-arginine has no effect on renal I/R injury in the model used in the present study, its administration increases the mRNA expression of NOS isoforms.
Research Laboratory of Pediatrics and Nephrology, Hungarian Academy of Sciences, Szentágothai János Knowledge Center, Budapest, Hungary.
Krisztina
K
Rusai
Andrea
A
Fekete
Beáta
B
Szebeni
Adám
A
Vannay
Géza
G
Bokodi
Veronika
V
Müller
Ondrej
O
Viklicky
Silvie
S
Bloudickova
Jan
J
Rajnoch
Uwe
U
Heemann
György
G
Reusz
András
A
Szabó
Tivadar
T
Tulassay
Attila J
AJ
Szabó
D000818:Animals; D001120:Arginine / Q000008:administration & dosage* / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D007191:Indazoles / Q000008:administration & dosage / Q000494:pharmacology; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics; D007668:Kidney / Q000098:blood supply* / Q000187:drug effects / Q000201:enzymology* / Q000503:physiopathology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology*; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000188:drug therapy / Q000201:enzymology* / Q000503:physiopathology; D013379:Substrate Specificity / Q000502:physiology; D015854:Up-Regulation / Q000502:physiology
D007191:Indazoles; D007527:Isoenzymes; D012333:RNA, Messenger; D009569:Nitric Oxide; D001120:Arginine; D052248:Nitric Oxide Synthase Type I; C080122:7-nitroindazole