Imaging the living inner ear using intravital confocal microscopy

Area of Science:

• Oto-rhino-laryngology
• Neuroscience
• Biomedical Engineering

Background:

• Confocal laser scanning microscopy enables deep tissue visualization in fluorescently labeled specimens.
• In vitro models using guinea pig temporal bones are limited by rapid tissue deterioration.
• A need exists for methods to study the cochlea in a preserved physiological state.

Purpose of the Study:

• To develop and validate an in vivo confocal microscopy model for the guinea pig cochlea.
• To enable real-time investigation of inner ear structures and cellular responses.
• To provide a tool for studying auditory physiology and hearing loss pathology.

Main Methods:

• Developed an in vivo surgical approach in anesthetized guinea pigs to expose the inner ear.
• Perfused scala tympani with fluorescent vital dyes (RH 795, calcein AM) for cellular labeling.
• Utilized a custom objective lens for intravital confocal microscopy with intact blood and nerve supply.

Main Results:

• Successfully visualized inner ear structures in a living animal model.
• Observed cellular changes, specifically shortening and swelling of sensory hair cells, after acoustic overstimulation.
• Demonstrated the feasibility of maintaining cochlear tissue in optimal condition for extended observation.

Conclusions:

• The developed in vivo intravital confocal microscopy model offers a significant advancement for auditory research.
• This model facilitates the study of dynamic processes in the cochlea under physiological conditions.
• It provides a powerful tool for investigating the mechanisms of hearing loss and potential therapeutic interventions.