Sodium valproate induces mitochondrial respiration dysfunction in HepG2 in vitro cell model

Area of Science:

• Biochemistry
• Cell Biology
• Pharmacology

Background:

• Sodium valproate (VPA) is an antiepileptic drug known for potential liver toxicity.
• Hepatotoxicity risk is elevated in patients with mitochondrial diseases, particularly those with POLG1 gene mutations.

Purpose of the Study:

• To investigate the effects of VPA on mitochondrial activity using an in vitro HepG2 cell model.
• To elucidate the mechanisms underlying VPA-induced hepatotoxicity, focusing on mitochondrial dysfunction.

Main Methods:

• HepG2 cells were cultured in glucose or galactose/pyruvate media and treated with VPA (0-2.0mM) for 24-72 hours.
• Assessed oxygen consumption rates, mitochondrial membrane potential, ATP levels, reactive oxygen species (ROS), and SOD2 protein expression.
• Evaluated cell death and cell number, and performed immunoblotting for key mitochondrial proteins.

Main Results:

• VPA decreased oxygen consumption and mitochondrial membrane potential in both media.
• VPA depleted ATP levels in galactose medium and increased ROS while decreasing SOD2 levels, indicating oxidative stress.
• VPA induced cell death and reduced cell count without altering specific mitochondrial protein levels.

Conclusions:

• VPA inhibits mitochondrial respiration and induces mitochondrial dysfunction, oxidative stress, and cell death.
• These findings suggest a critical role for mitochondria in the pathogenesis of VPA-induced hepatotoxicity.
• A novel pathomechanism involving impaired ROS elimination may contribute to VPA toxicity.