Protective role of morin, a flavonoid, against high glucose induced oxidative stress mediated apoptosis in primary rat hepatocytes

PLoS One. 2012;7(8):e41663. doi: 10.1371/journal.pone.0041663. Epub 2012 Aug 10.

Abstract

Apoptosis is an early event of liver damage in diabetes and oxidative stress has been linked to accelerate the apoptosis in hepatocytes. Therefore, the compounds that can scavenge ROS may confer regulatory effects on high-glucose induced apoptosis. In the present study, primary rat hepatocytes were exposed to high concentration (40 mM) of glucose. At this concentration decreased cell viability and enhanced ROS generation was observed. Depleted antioxidant status of hepatocytes under high glucose stress was also observed as evident from transcriptional level and activities of antioxidant enzymes. Further, mitochondrial depolarisation was accompanied by the loss of mitochondrial integrity and altered expression of Bax and Bcl-2. Increased translocation of apoptotic proteins like AIF (Apoptosis inducing factor) & Endo-G (endonuclease-G) from its resident place mitochondria to nucleus was also observed. Cyt-c residing in the inter-membrane space of mitochondria also translocated to cytoplasm. These apoptotic proteins initiated caspase activation, DNA fragmentation, chromatin condensation, increased apoptotic DNA content in glucose treated hepatocytes, suggesting mitochondria mediated apoptotic mode of cell death. Morin, a dietary flavonoid from Psidium guajava was effective in increasing the cell viability and decreasing the ROS level. It maintained mitochondrial integrity, inhibited release of apoptotic proteins from mitochondria, prevented DNA fragmentation, chromatin condensation and hypodiploid DNA upon exposure to high glucose. This study confirms the capacity of dietary flavonoid Morin in regulating apoptosis induced by high glucose via mitochondrial mediated pathway through intervention of oxidative stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / pharmacology*
  • Apoptosis / drug effects*
  • Apoptosis / genetics
  • Caspase 3 / genetics
  • Caspase 3 / metabolism
  • Caspase 9 / genetics
  • Caspase 9 / metabolism
  • DNA Fragmentation / drug effects
  • Flavonoids / pharmacology*
  • Gene Expression Regulation / drug effects
  • Glucose / toxicity
  • Hepatocytes / drug effects*
  • Hepatocytes / metabolism*
  • Lactate Dehydrogenases / metabolism
  • Male
  • Matrix Metalloproteinases / metabolism
  • Membrane Potential, Mitochondrial / drug effects
  • Oxidative Stress*
  • Protein Transport / drug effects
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Rats
  • Rats, Wistar
  • Reactive Oxygen Species / metabolism
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / metabolism
  • Transcription, Genetic / drug effects
  • bcl-2-Associated X Protein / genetics

Substances

  • Antioxidants
  • Flavonoids
  • Proto-Oncogene Proteins c-bcl-2
  • Reactive Oxygen Species
  • bcl-2-Associated X Protein
  • morin
  • Lactate Dehydrogenases
  • Superoxide Dismutase
  • Caspase 3
  • Caspase 9
  • Matrix Metalloproteinases
  • Glucose

Grants and funding

This work was supported by Indian Council of Medical Research, New Delhi and Supra-Institutional Project-08 of Council of Scientific & Industrial Research (CSIR). The funding agencies approved the broad study design. They had no role in data collection and analysis, preparation of the manuscript or decision to publish.