Lignin-derived lignophenols attenuate oxidative and inflammatory damage to the kidney in streptozotocin-induced diabetic rats

Abstract

This study investigated the effects of lignin-derived lignophenols (LPs) on the oxidative stress and infiltration of macrophages in the kidney of streptozotocin (STZ)-induced diabetic rats. The diabetic rats were divided into four groups with 0%, 0.11%, 0.33% and 1.0% LP diets. The vehicle-injected controls were given a commercial diet. At 5 weeks, superoxide (O₂⁻) production, macrophage kinetics, the degree of fibrosis in glomeruli and mRNA expression for monocyte chemoattractant protein-1 (MCP-1) were examined. The NADPH-stimulated O₂⁻ levels in the kidney of the diabetic rats treated with 1.0% LP were significantly lower than those in untreated diabetic rats. The number of macrophages, levels of MCP-1 mRNA expression and degree of glomerular fibrosis increased in untreated LP and these levels were significantly lower in 1.0%LP-treated rats. The results suggested that LPs suppress the excess oxidative stress, the infiltration and activation of macrophages and the glomerular expansion in STZ-induced diabetic kidneys.

Keywords::

• Lignophenols
• superoxide
• monocyte chemoattractant protein-1
• macrophage
• fibrosis
• diabetic nephropathy

Acknowledgements

This study was supported by a Grant-in-Aid (no.19650211) for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

This paper was first published online on Early Online on 30 September 2009.