Antidiabetic activities of polysaccharides separated from Inonotus obliquus via the modulation of oxidative stress in mice with streptozotocin-induced diabetes

PLoS One. 2017 Jun 29;12(6):e0180476. doi: 10.1371/journal.pone.0180476. eCollection 2017.

Abstract

This study evaluated the effects of Inonotus obliquus polysaccharides (IOs) on diabetes and other underlying mechanisms related to inflammatory factors and oxidative stress in a mouse model of streptozotocin (STZ)-induced diabetes. Four weeks administration of metformin (120 mg/kg) and IO1-4 (50%-80% alcohol precipitation), or IO5 (total 80% alcohol precipitation) at doses of 50 mg/kg reverses the abnormal changes of bodyweights and fasting blood glucose levels of diabetic mice. IOs significantly increased the insulin and pyruvate kinase levels in serum, and improved the synthesis of glycogen, especially for IO5. IOs restored the disturbed serum levels of superoxide dismutase, catalase, glutathione peroxidase, and malondialdehyde. The down-regulation of interleukin-2 receptor, matrix metalloproteinase-9, and the enhancement of interleukin-2 in serum of diabetic mice were significantly attenuated by IOs. Histologic and morphology examinations showed that IOs repaired the damage on kidney tissues, inhibited inflammatory infiltrate and extracellular matrix deposit injuries in diabetic mice. Compared with untreated diabetic mice, IOs decreased the expression of phosphor-NF-κB in the kidneys. These results show that IOs treatment attenuated diabetic and renal injure in STZ-induced diabetic mice, possibly through the modulation of oxidative stress and inflammatory factors. These results provide valuable evidences to support the use of I. obliquus as a hypoglycemic functional food and/or medicine.

MeSH terms

  • Animals
  • Basidiomycota / chemistry*
  • Diabetes Mellitus, Experimental / drug therapy*
  • Glycated Hemoglobin A / metabolism
  • Hypoglycemic Agents / pharmacology*
  • Hypoglycemic Agents / therapeutic use
  • Insulin / blood
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Oxidative Stress / drug effects*
  • Polysaccharides / pharmacology*
  • Polysaccharides / therapeutic use
  • Pyruvate Kinase / blood
  • Streptozocin

Substances

  • Glycated Hemoglobin A
  • Hypoglycemic Agents
  • Insulin
  • Polysaccharides
  • Streptozocin
  • Pyruvate Kinase

Grant support

The manuscript has been supported by the funding of Science and Technology Key Project in Jilin Province of China (Grant No. 20140311072YY, 20150203002NY and 20160204029YY). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.