Histologic analyses, including cytocochleograms, allows for exact counting of hair cells and ribbon synapses.
Hair cells are delicate ciliated cells in the cochlea that convert mechanical sound waves into electric signals. These cells and the specialized connections they make to the auditory nerve (called ribbon synapses) are among the most fragile structures in the entire auditory pathway. A cytocochleogram is an FDA-recommended histologic analysis of the cochlea that provides a quantitative analysis of hair cells and ribbon synapses. A fluorescent stain labels hair cells, and confocal laser microscopy is used to count the cells that are both present/viable, and those that are missing (depicted below by white arrows) as a result of sound, drug, or chemical exposure.
Confocal microscopy can also be used to analyze and count ribbon synapses. Turner Scientific uses myosin VIIa as a stain for viable hair cells, and C-terminal binding protein 2 (ctbp-2) as a stain for post-synaptic auditory nerve fibers at the ribbon synapse (depicted to the right).
The analysis of cytocochleograms is a specialized process that requires unique training and experience. Dr. Brandon Cox has been performing cytocochleogram testing for over ten years and leads Turner Scientific's histologic efforts.