Benoxaprofen induced toxicity in isolated rat hepatocytes

Area of Science:

• Hepatology
• Toxicology
• Pharmacology

Background:

• Benoxaprofen is a non-steroidal anti-inflammatory drug (NSAID).
• NSAIDs can cause liver toxicity through various mechanisms.
• Understanding benoxaprofen's specific toxicity pathway is crucial.

Purpose of the Study:

• To investigate the toxicity mechanisms of benoxaprofen in rat hepatic systems.
• To determine the role of cytochrome P-450 in benoxaprofen-induced hepatotoxicity.
• To elucidate the cellular events leading to benoxaprofen toxicity.

Main Methods:

• Incubation of benoxaprofen with rat hepatic microsomes and isolated hepatocytes.
• Measurement of aminopyrine metabolism inhibition.
• Assessment of intracellular lactate/pyruvate ratio and alanine aminotransferase release.
• Evaluation of effects following phenobarbitone (PB) or 3-methylcholanthrene (3-MC) pretreatment.
• Testing the impact of cytochrome P-450 inhibitors.

Main Results:

• Benoxaprofen competitively inhibited aminopyrine metabolism in microsomes.
• Significant hepatocyte toxicity was observed, indicated by increased lactate/pyruvate ratio and ALT release.
• Toxicity showed a dose-response relationship and was not modulated by PB or 3-MC pretreatment.
• Cytochrome P-450 inhibitors did not alter benoxaprofen's toxicity.
• Evidence of plasma membrane bleb formation and altered cellular redox state was noted.

Conclusions:

• Hepatic cytochrome P-450 metabolism is likely not involved in benoxaprofen's hepatotoxicity.
• Benoxaprofen may induce toxicity by uncoupling oxidative phosphorylation.
• Disturbance of intracellular calcium ion homeostasis is a potential mechanism of benoxaprofen toxicity.