A mouse model of mitochondrial complex III dysfunction induced by myxothiazol

Area of Science:

• Biochemistry
• Mitochondrial Biology
• Pharmacology

Background:

• Myxothiazol is a known inhibitor of respiratory chain complex III (CIII), targeting the ubiquinol oxidation site.
• It is commonly used as a research tool in in vitro and cell culture studies of mitochondrial function.
• Existing models for studying CIII inhibition in vivo are limited.

Purpose of the Study:

• To develop and characterize a mouse model of biochemically induced and reversible CIII inhibition using myxothiazol.
• To assess the impact of sustained CIII inhibition on liver histology, lipid content, supercomplex formation, and gene expression.
• To establish a reliable in vivo system for investigating mitochondrial hepatopathies.

Main Methods:

• C57Bl/J6 mice were administered myxothiazol (0.56 mg/kg) intraperitoneally every 24 hours.
• Liver samples were analyzed for CIII activity, histology, lipid content, and mitochondrial supercomplex formation.
• Gene expression analysis was performed to detect markers of hepatotoxicity and inflammation.

Main Results:

• Myxothiazol administration induced a reversible decrease in CIII activity to 50% of control levels within 2 hours post-injection.
• After four days of treatment, only minor liver histological changes were observed.
• Mitochondrial supercomplex formation remained preserved, and no significant changes in genes related to hepatotoxicity or inflammation were detected.

Conclusions:

• Myxothiazol-induced CIII inhibition in mice is reversible and can be maintained for at least four days without significant hepatotoxicity or lethality.
• This novel mouse model provides a valuable tool for studying respiratory chain function.
• The model holds potential for evaluating pharmacological interventions for mitochondrial liver diseases (hepatopathies).