The thromboxane receptor antagonist S18886 attenuates renal oxidant stress and proteinuria in diabetic apolipoprotein E-deficient mice.
Arachidonic acid metabolites, some of which may activate thromboxane A(2) receptors (TPr) and contribute to the development of diabetes complications, including nephropathy, are elevated in diabetes. This study determined the effect of blocking TPr with S18886 or inhibiting cyclooxygenase with aspirin on oxidative stress and the early stages of nephropathy in streptozotocin-induced diabetic apolipoprotein E(-/-) mice. Diabetic mice were treated with S18886 (5 mg . kg(-1) . day(-1)) or aspirin (30 mg . kg(-1) . day(-1)) for 6 weeks. Neither S18886 nor aspirin affected hyperglycemia or hypercholesterolemia. There was intense immunohistochemical staining for nitrotyrosine in diabetic mouse kidney. In addition, a decrease in manganese superoxide dismutase (MnSOD) activity was associated with an increase in MnSOD tyrosine-34 nitration. Tyrosine nitration was significantly reduced by S18886 but not by aspirin. Staining for the NADPH oxidase subunit p47(phox), inducible nitric oxide synthase, and 12-lipoxygenase was increased in diabetic mouse kidney, as were urine levels of 12-hydroxyeicosatetraenoic acid and 8-iso-prostaglandin F(2alpha). S18886 attenuated all of these markers of oxidant stress and inflammation. Furthermore, S18886 significantly attenuated microalbuminuria in diabetic mice and ameliorated histological evidence of diabetic nephropathy, including transforming growth factor-beta and extracellular matrix expression. Thus, in contrast to inhibiting cyclooxygenase, blockade of TPr may have therapeutic potential in diabetic nephropathy, in part by attenuating oxidative stress.
Xu
Shanqin
S
Vascular Biology Unit, Boston University Medical Center, 650 Albany Street X704, Boston, MA 02118, USA.
Jiang
Bingbing
B
Maitland
Karlene A
KA
Bayat
Hossein
H
Gu
Jiali
J
Nadler
Jerry L
JL
Corda
Stefano
S
Lavielle
Gilbert
G
Verbeuren
Tony J
TJ
Zuccollo
Adriana
A
Cohen
Richard A
RA
D000818:Animals; D001057:Apolipoproteins E / Q000172:deficiency* / Q000235:genetics; D001092:Arachidonate 12-Lipoxygenase / Q000378:metabolism; D001241:Aspirin / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000150:complications* / Q000378:metabolism*; D005260:Female; D017353:Gene Deletion; D007674:Kidney Diseases / Q000188:drug therapy / Q000473:pathology; D051379:Mice; D019255:NADPH Oxidases; D009281:Naphthalenes / Q000494:pharmacology* / Q000627:therapeutic use; D052247:Nitric Oxide Synthase Type II; D018384:Oxidative Stress / Q000187:drug effects*; D010750:Phosphoproteins / Q000378:metabolism; D011422:Propionates / Q000494:pharmacology* / Q000627:therapeutic use; D011507:Proteinuria / Q000150:complications / Q000188:drug therapy / Q000378:metabolism*; D017482:Receptors, Thromboxane / Q000037:antagonists & inhibitors* / Q000378:metabolism
D001057:Apolipoproteins E; D009281:Naphthalenes; D010750:Phosphoproteins; D011422:Propionates; D017482:Receptors, Thromboxane; C501362:terutroban; D001092:Arachidonate 12-Lipoxygenase; D052247:Nitric Oxide Synthase Type II; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D001241:Aspirin