Neuropathologic findings associated with seizures in FVB mice

Area of Science:

• Neuroscience
• Pathology
• Genetics and Transgenic Research

Background:

• FVB mice are widely used in transgenic research due to their genetic background and reproductive capabilities.
• While seizures are documented in other mouse strains, their occurrence in the FVB strain has not been systematically evaluated.
• This study addresses a critical knowledge gap regarding seizure activity in FVB mice.

Purpose of the Study:

• To investigate and characterize a previously unrecognized epileptic syndrome in FVB mice.
• To determine the pathological findings associated with seizures in this mouse strain.
• To assess the potential impact of this syndrome on transgenic research.

Main Methods:

• Pathologic examination of affected nonmanipulated and transgenic FVB/N mice (n=68).
• Gross and microscopic evaluation of brain and liver tissues.
• Special stains, electron microscopy, and cell culture assays to rule out infectious agents.

Main Results:

• Neuronal necrosis in the cerebral cortex, hippocampus, and thalamus was observed in all examined mice.
• Hepatocellular necrosis was present in a subset of mice (19/68), interpreted as agonal changes.
• No infectious agents were detected, suggesting a non-infectious etiology for the observed syndrome.

Conclusions:

• FVB mice exhibit a previously unrecognized, often lethal epileptic syndrome characterized by ischemic neuronal necrosis.
• The observed neuropathology is consistent with status epilepticus in humans.
• This seizure syndrome may significantly impact the reliability and outcomes of transgenic research utilizing FVB mice.