Abstract
Simple SummaryHearing is arguably the primary sensory and communication channel for cetaceans. The study of diverse physiological and pathological events involving this system, requires standardized and reliable protocols for processing valuable and scarce samples such as the ears of cetaceans. As part of our research, standardized tissue processing protocols were developed in order to improve our knowledge regarding the anatomy and pathological changes of this sensorial system, including the nervous structures of the ear. The results obtained suggest that ethylenediaminetetraacetic acid (EDTA)-based decalcifying solutions are key for correct evaluation of bony tissue structures such as the ear of cetaceans.Cetaceans greatly depend on their hearing system to perform many vital activities. The spiral ganglion is an essential component of the auditory pathway and can even be associated with injuries caused by anthropogenic noise. However, its anatomical location, characterized by surrounding bony structures, makes the anatomical and anatomopathological study of the spiral ganglion a difficult task. In order to obtain high-quality tissue samples, a perfect balance between decalcification and the preservation of neural components must be achieved. In this study, different methodologies for spiral ganglion sample preparation and preservation were evaluated. Hydrochloric acid had the shortest decalcification time but damaged the tissue extensively. Both formic acid and EDTA decalcification solutions had a longer decalcification time but exhibited better preservation of the neurons. However, improved cell morphology and staining were observed on ears pretreated with EDTA solution. Therefore, we suggest that decalcifying methodologies based on EDTA solutions should be used to obtain the highest quality samples for studying cell morphology and antigenicity in cetacean spiral ganglion neurons.
Highlights
The hearing system is possibly the main sensory system of cetaceans, acting as their principal communication channel [1]
The conservation of antigenicity in our research was better preserved with 20% EDTA compared with hydrochloric acid and 10% EDTA
Obtaining samples from cetaceans in a good state of conservation is very complicated, so having standardized decalcification protocols is critical to allow the correct evaluation of tissue samples
Summary
The hearing system is possibly the main sensory system of cetaceans, acting as their principal communication channel [1]. Well-preserved inner-ear samples from stranded cetaceans are scarce, so it is paramount to develop protocols for sample collection, preservation, and processing. We will focus on the development of different strategies to accurately preserve the inner ear, the spiral ganglion of cetaceans. About 95% of the ganglion cells are classified as type I, which are connected to the inner hair cells in the organ of Corti. The remaining 5% correspond to type II ganglion cells, which connect to the outer hair cells of the organ of Corti [11]. These connections are produced through the peripheral processes of the ganglion cells. The central processes of these cells come together to form the acoustic portion of the cochlear nerve and end up the cochlear nucleus in the brainstem [12]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
