Journal Article

Tranilast attenuates the up-regulation of thioredoxin-interacting protein and oxidative stress in an experimental model of diabetic nephropathy

Sih Min Tan, Yuan Zhang, Alison J. Cox, Darren J. Kelly and Weier Qi

in Nephrology Dialysis Transplantation

Published on behalf of European Renal Association - European Dialysis and Transplant Assoc

Volume 26, issue 1, pages 100-110
Published in print January 2011 | ISSN: 0931-0509
Published online June 2010 | e-ISSN: 1460-2385 | DOI: http://dx.doi.org/10.1093/ndt/gfq355
Tranilast attenuates the up-regulation of thioredoxin-interacting protein and oxidative stress in an experimental model of diabetic nephropathy

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Background. Diabetic nephropathy is the leading cause of kidney failure in the developed world. Tranilast has been reported to not only act as an anti-inflammatory and anti-fibrotic compound, but it also exerts anti-oxidative stress effects in diabetic nephropathy. Thioredoxin-interacting protein (Txnip) is the endogenous inhibitor of the anti-oxidant thioredoxin and is highly up-regulated in diabetic nephropathy, leading to oxidative stress and fibrosis. In this study, we aimed to investigate whether tranilast exerts its anti-oxidant properties through the inhibition of Txnip.

Methods. Heterozygous Ren-2 rats were rendered diabetic with streptozotocin. Another group of rats were injected with citrate buffer alone and treated as non-diabetic controls. After 6 weeks of diabetes, diabetic rats were divided into two groups: one group gavaged with tranilast at 200 mg/kg/day and another group with vehicle.

Results. Diabetic rats had a significant increase in albuminuria, tubulointerstitial fibrosis, peritubular collagen IV accumulation, reactive oxygen species (ROS) and macrophage infiltration (all P < 0.05). These changes were associated with an increase in Txnip mRNA and protein expression in the tubules and glomeruli of diabetic kidney. Treatment with tranilast for 4 weeks significantly attenuated Txnip up-regulation in diabetic rats and this was associated with a reduction in ROS, fibrosis and macrophage infiltration (all P < 0.05).

Conclusions. This is the first study to demonstrate that tranilast not only has anti-inflammatory and anti-fibrotic effects as previously reported but also attenuates the up-regulation of Txnip and oxidative stress in diabetic nephropathy.

Keywords: diabetic nephropathy; fibrosis; oxidative stress; thioredoxin-interacting protein

Journal Article.  5434 words.  Illustrated.

Subjects: Nephrology

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