Nitric oxide synthase isoform expression in acute versus chronic anti-Thy 1 nephritis.
BACKGROUND
Two inbred Lewis rat substrains (LEW/Moe, LEW/Maa) were identified responding differently to induction of anti-Thy 1 glomerulonephritis (aThy 1-GN). LEW/Moe rats show an acute mesangioproliferative glomerulonephritis with rapid healing of glomerular lesions within four weeks, while LEW/Maa rats develop severe glomerular injury followed by chronic glomerular sclerosis and persistent albuminuria. We investigated whether the glomerular expression pattern of nitric oxide synthase (NOS) isoforms could explain these substrain-related differences.


METHODS
Rats (N = 5 to 7 per group) were investigated in a time course experiment. Severity of aThy 1-GN was determined by albuminuria measurements, glomerular matrix score and microaneurysm formation. Glomerular gene expression of NOS isoforms was determined by semiquantitative RT-PCR. Inducible NOS (iNOS) activity was determined in cultured glomeruli and peritoneal macrophages. Neuronal NOS (nNOS) protein expression was detected by Western blotting and enzyme histochemistry. Plasma renin activity (PRA) was measured by RIA.


RESULTS
Induction of iNOS expression and activity was found significantly increased and sustained in LEW/Maa vs. LEW/Moe rats associated with an increased number of infiltrating macrophages and with an increased capacity of iNOS-expression and iNOS-activation by isolated macrophages in LEW/Maa rats. Glomerular nNOS mRNA and nNOS protein expression were constitutively increased in LEW/Maa rats. Renal nNOS localization was restricted to the macula densa region in both substrains and associated with increased PRA in LEW/Maa rats. No difference in glomerular endothelial NOS-mRNA expression between the substrains was observed.


CONCLUSIONS
Increased glomerular iNOS and nNOS expression were associated with chronic anti-Thy 1 glomerulonephritis in LEW/Maa rats and may contribute to glomerular damage by separate mechanisms.
Ketteler
Markus
M
Department of Medicine II, University Hospital Aachen, Pauwelsstrasse 30, D-52057 Aachen, Germany. mketteler@ukaachen.de
Westenfeld
Ralf
R
Gawlik
Alexander
A
Bachmann
Sebastian
S
Frey
Alexander
A
Schönfelder
Gilbert
G
Paul
Martin
M
Distler
Armin
A
de Heer
Emile
E
D000208:Acute Disease; D000818:Animals; D002908:Chronic Disease; D007518:Isoantibodies / Q000276:immunology*; D009393:Nephritis / Q000201:enzymology* / Q000276:immunology*; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew
D007518:Isoantibodies; D012333:RNA, Messenger; C035678:anti-Thy antibody; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; C496322:Nos1 protein, rat; C496318:Nos2 protein, rat