Cochlear pathology following exposure to mercury.

Area of Science:

• Ototoxicology
• Neuroscience
• Cell Biology

Background:

• Mercury chloride is a known ototoxin.
• Exposure can lead to morphological changes in the cochlea.
• Understanding the specific cellular targets is crucial for assessing hearing loss.

Purpose of the Study:

• To investigate the morphological changes in the sensory and secretory epithelia of the cochlea after mercury chloride exposure.
• To differentiate the effects of acute versus chronic mercury chloride intoxication on cochlear structures.

Main Methods:

• Morphological examination of cochlear tissues.
• Cytocochleogram studies to map damage distribution.
• Histopathological analysis of sensory epithelia, nerve terminals, hair cells, and stria vascularis.

Main Results:

• Earliest and most severe damage observed in the apical cochlear part of the sensory epithelium.
• Basal cochlear coils showed infrequent damage.
• Acute intoxication primarily impacted afferent and efferent nerve terminals and hair cells.
• Chronic poisoning additionally affected the stria vascularis.

Conclusions:

• Mercury chloride induces significant morphological alterations in the cochlea.
• Damage patterns vary between acute and chronic exposure, affecting different cochlear components.
• These findings highlight the ototoxic potential of mercury chloride on auditory structures.