Selective nuclear factor kappa-B inhibitors, pyrolidium dithiocarbamate and sulfasalazine, prevent the nephrotoxicity induced by gentamicin.
OBJECTIVE
To investigate the effect of selective nuclear factor kappa-B (NFkappa-B) inhibitors, pyrolidium dithiocarbamate (PD) and sulfasalazine (SZ) on renal tubular necrosis and inducible nitric oxide synthase (iNOS) and NFkappa-B expression induced by gentamicin in rats.


METHODS
In all, 48 adult male Sprague-Dawley rats were divided into six equal groups; group 1, control; group 2, injected with gentamicin for 10 days (100 mg/kg/day, intraperitoneal, i.p.); group 3, injected with gentamicin plus PD (100 mg/kg/day, i.p.); group 4, injected with gentamicin plus SZ (75 mg/kg/day, i.p.); group 5, injected with gentamicin plus distilled water (vehicle for PD); and group 6, injected with gentamicin plus ammonium hydroxide (75 mg/day, 1 m, vehicle for SZ) for 10 days. At 24 h after the last injection, rats were killed and the renal cortex separated from the medulla. A small sample was fixed in formaldehyde solution for histological and immunohistochemical examination. Blood samples were also taken to assess the serum levels of urea, creatinine, Na(+), K(+) and gamma-glutamyl transpeptidase (GT). Crude extracts of the cortex were used to determine reduced glutathione (GSH-Px), NO and malondialdehyde (MDA). Immunohistochemically, iNOS and the active subunit of NFkappaB, P65, were evaluated using mouse monoclonal antibodies.


RESULTS
On haematoxylin and eosin staining, compared with the controls rats, gentamicin caused widespread tubular necrosis (grade 3 and 4) but in group 3 and 4 there was a marked reduction in the extent of tubular damage. Immunohistochemically there was more marked staining for iNOS and P65 expression in rats given gentamicin than in the control and group 3 and 4 (P < 0.001). In groups 3 and 4 iNOS and P65 expression were significantly less than in rats given only gentamicin. There was no significant difference in serum levels of Na(+), K(+), blood urea nitrogen and creatinine. Compared with control rats, gentamicin caused hyperproteinuria, a marked increase in levels of serum gamma-GT, MDA and NO, and a decrease in GSH-Px (P < 0.001).


CONCLUSIONS
These results indicate that gentamicin induces iNOS expression through activation of NFkappa-B (P65). It is possible to prevent gentamicin-induced nephrotoxicity using selective NFkappa-B inhibitors.
Tugcu
Volkan
V
Department of Urology, Bakýrköy Dr. Sadi Konuk Research and Training Hospital, Istanbul, Turkey. volkantugcu@yahoo.com
Ozbek
Emin
E
Tasci
Ali I
AI
Kemahli
Eray
E
Somay
Adnan
A
Bas
Muzaffer
M
Karaca
Cetin
C
Altug
Tuncay
T
Cekmen
Mustafa B
MB
Ozdogan
Haci K
HK
D000818:Animals; D005839:Gentamicins / Q000633:toxicity*; D020672:I-kappa B Proteins / Q000627:therapeutic use*; D007150:Immunohistochemistry; D007674:Kidney Diseases / Q000139:chemically induced* / Q000378:metabolism / Q000517:prevention & control; D008297:Male; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D011759:Pyrrolidines / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012460:Sulfasalazine / Q000627:therapeutic use*; D013859:Thiocarbamates / Q000627:therapeutic use*
D005839:Gentamicins; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; C000606206:Nfkbia protein, rat; D011759:Pyrrolidines; D013859:Thiocarbamates; D000072000:NF-KappaB Inhibitor alpha; C020972:pyrrolidine dithiocarbamic acid; D012460:Sulfasalazine; D052247:Nitric Oxide Synthase Type II