Related Experiment Videos
Methylcobalamin as antagonist to transient ototoxic action of gentamicin
1Department of Otolaryngology-Head and Neck Surgery, Shanghai Renji Hospital, People's Republic of China. hospital@renji.com
Abstract:
The objective of this study was to determine whether methylcobalamin inhibits the ototoxic action of gentamicin. Fourteen pigmented guinea pigs were randomly divided into experimental and control groups. Each animal in the experimental group was given a large single dose of gentamicin (125 mg/kg i.m.), followed by immediate administration of methylcobalamin (1 mg kg i.m.). In the control group, the animals received gentamicin only, at the same dose as the experimental group. The compound action potentials (CAPs) in the right ears of animals were measured using a signal processor before and 15, 30, 45, 60 and 75 min after injection of the drugs. The sound stimulus was presented by means of clicks and tone pips at 2, 4 and 8 kHz. Following the electro-physiological tests, the animal was sacrificed and prepared for scanning electron microscopic observation. There was prolongation of latency and diminution of amplitude of CAPs N1 and N2 15 min after injection of gentamicin. Although the N1-N2 intervals increased as the time after injection of gentamicin increased, the variations were still within normal ranges. In contrast, there was no prolongation of N1 latencies or N1-N2 intervals 30 min after injection in the experimental group. There were no marked changes in N1 or N2 amplitudes, compared with the results before injection, in the experimental group. The firing mechanism of the inner ear may be affected by a single dose of gentamicin. This suggests that the transient ototoxic action of gentamicin hardly affected the conductive function of the nerve fibres, even though the firing function of the inner ear was influenced. Methylcobalamin may inhibit the ototoxic side effects of gentamicin.
Insights
Methylcobalamin may protect against gentamicin-induced ototoxicity. This study found that methylcobalamin administration shortly after gentamicin injection prevented negative impacts on auditory nerve function in guinea pigs.
Area of Science:
- Ototoxicity research
- Neuropharmacology
- Auditory neuroscience
Background:
- Gentamicin is a common antibiotic with known ototoxic side effects.
- Ototoxicity can lead to hearing loss and balance disorders.
- Preventive strategies against gentamicin-induced ototoxicity are of significant clinical interest.
Purpose of the Study:
- To investigate the potential protective effect of methylcobalamin against gentamicin-induced ototoxicity.
- To evaluate the impact of methylcobalamin on auditory nerve function following gentamicin exposure.
Main Methods:
- The study utilized a guinea pig model, randomly assigning animals to experimental (gentamicin + methylcobalamin) and control (gentamicin only) groups.
- Compound action potentials (CAPs) were measured in the auditory nerve before and at various time points after drug administration.
- Electrophysiological data was supplemented with scanning electron microscopy for structural analysis.
Main Results:
- Gentamicin administration alone caused transient prolongation of latency and diminished amplitude of CAPs N1 and N2.
- In the experimental group, methylcobalamin administration prevented the prolongation of N1 latencies and N1-N2 intervals.
- No significant changes in CAP amplitudes were observed in the methylcobalamin-treated group.
Conclusions:
- A single dose of gentamicin can transiently affect inner ear function.
- Methylcobalamin appears to inhibit the ototoxic side effects of gentamicin.
- Methylcobalamin may preserve the conductive function of nerve fibers despite transient effects on inner ear firing mechanisms.