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Molecular mechanism of diclofenac hepatotoxicity: Association of cell injury with oxidative metabolism and decrease

X Ponsoda1, R Bort, R Jover

  • 1Unidad de Hepatología Experimental, Centro de Investigación Hospital Universitario "La Fe", SVS. Avda. Campanar 21, E-46009 Valencia, Spain.

Toxicology in Vitro : an International Journal Published in Association with BIBRA
|July 24, 2010
PubMed

Insights

Diclofenac-induced liver injury is linked to its oxidative metabolism, not oxidative stress. Impaired mitochondrial ATP production is the likely cause of diclofenac hepatotoxicity.

Area of Science:

  • Hepatology
  • Toxicology
  • Biochemistry

Background:

  • Diclofenac is a common nonsteroidal anti-inflammatory drug (NSAID).
  • Case reports suggest diclofenac may cause more liver injury than previously recognized.
  • The molecular mechanisms underlying diclofenac-associated hepatitis require elucidation.

Purpose of the Study:

  • To investigate the molecular mechanisms of diclofenac-induced hepatotoxicity.
  • To correlate diclofenac metabolism with cellular toxicity.
  • To identify the primary cellular events leading to liver injury.

Main Methods:

  • Assessed diclofenac cytotoxicity in metabolizing (rat hepatocytes) and non-metabolizing liver cells (HepG2, FaO).
  • Monitored changes in calcium homeostasis, glutathione (GSH), lipid peroxidation, and ATP levels.
  • Examined diclofenac metabolism and its relationship to cytotoxicity.
  • Utilized fructose incubation to assess the role of ATP production.

Main Results:

  • Diclofenac toxicity correlated with its oxidative metabolism and a specific minor oxidation metabolite.
  • Inhibiting diclofenac metabolism reduced drug-induced cytotoxicity.
  • Hepatocyte injury was preceded by a significant decrease in ATP levels.
  • No evidence of oxidative stress (GSH depletion, lipid peroxidation) was observed at early stages.
  • Fructose administration prevented diclofenac cytotoxicity, indicating a role for ATP depletion.

Conclusions:

  • Diclofenac hepatotoxicity is primarily driven by impaired mitochondrial ATP production.
  • The toxicity is associated with the drug's oxidative metabolism, not direct oxidative stress.
  • Understanding these mechanisms can inform strategies to mitigate diclofenac-induced liver injury.

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