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Differences in the cochlear degeneration pattern in the guinea pig as a result of gentamicin and cis-platinum
Abstract:
This study gives the results of a series of studies on inner ears carried out with the help of microdissections and surface preparations. The total degeneration patterns of the cochlea of the guinea pig due to two different ototoxic drugs were investigated with this technique. Clear differences between the results of the ototoxic drugs (gentamicin and cis-platinum) in the inner ear were observed. Gentamicin has a 'typical starting point' of degeneration on the basilar membrane. From this 'degeneration point' the loss of hair cells progressed towards the round window (fast) and the apex (slowly). The stria vascularis showed no signs of degeneration due to gentamicin. Reissner's membrane, on the other hand, showed cellular vacuolization of the endolymphatic cells. Cis-platinum (DDP) showed no 'degeneration point'; the loss of hair cells was found over the complete length of the basilar membrane, with a preference for the basilar turn. The stria vascularis, on the other hand, showed severe degenerative changes due to DDP, whereas Reissner's membrane showed no change. In using the microdissection technique we were in a position to discover these differences between the two ototoxic drugs.
Insights
This study reveals distinct inner ear damage patterns from gentamicin and cis-platinum ototoxic drugs in guinea pigs. Microdissection highlights unique hair cell loss and tissue degeneration differences between these agents.
Area of Science:
- Ototoxicology
- Auditory Neuroscience
- Comparative Pathology
Background:
- Ototoxic drugs, such as gentamicin and cis-platinum, are known to cause damage to the inner ear.
- Understanding the specific patterns of cochlear degeneration induced by these drugs is crucial for developing protective strategies.
Purpose of the Study:
- To investigate and compare the cochlear degeneration patterns caused by gentamicin and cis-platinum in guinea pigs.
- To elucidate the differential effects of these two ototoxic drugs on hair cells, stria vascularis, and Reissner's membrane.
Main Methods:
- Microdissection and surface preparation techniques were employed to examine the cochleae of guinea pigs.
- Detailed analysis of hair cell loss, stria vascularis integrity, and Reissner's membrane changes was performed.
Main Results:
- Gentamicin induced a specific 'degeneration point' on the basilar membrane, with hair cell loss progressing towards the apex and round window; Reissner's membrane showed vacuolization, but the stria vascularis remained unaffected.
- Cis-platinum (DDP) caused widespread hair cell loss along the entire basilar membrane, particularly in the basal turn, without a distinct 'degeneration point'.
- DDP induced severe degenerative changes in the stria vascularis, while Reissner's membrane showed no alterations.
Conclusions:
- Microdissection revealed clear, distinct patterns of cochlear damage between gentamicin and cis-platinum.
- The observed differences in degeneration patterns highlight the drug-specific ototoxicity, aiding in understanding and potentially mitigating inner ear damage.