Establishment of a Gentamicin Cochlear Poisoning Model in Guinea Pigs and Cochlear Nerve Endings Recognition of Ultrasound Signals
Fusen Wang, Shusheng Gong, Yuee Zhou, Chengcheng Huang, Tiegang Li, Qian Li, Xinyu Ceng, Chaoyan Wang
Medical Science Monitor 2018 · 10.12659/msm.913205
Abstract
BACKGROUND Aminoglycosides, a type of gram-negative antibacterial, are broad-spectrum antibiotics that are highly potent and have satisfactory therapeutic efficacy in the treatment of life-threatening infections. Our study aimed to establish a gentamicin-induced cochlear injury model and to investigate the cochlear nerve endings' recognition of ultrasound signals. MATERIAL AND METHODS A guinea pig cochlear injury model was established by intraperitoneal injection of gentamycin. Auditory brainstem response (ABR) and fMRI an affected cerebral cortex region of interest (ROI) of the cerebral cortex blood oxygenation level dependent (BOLD) effect was induced by bone-conducted ultrasound. Immunofluorescence was used to detect expression of Prestin in outer hair cells, Otoferlin in inner hair cells, and cochlear hair cell microfilament protein (F-Actin). RESULTS For 30-35 KHz bone-conducted ultrasound, the induction rate of ABR threshold or ROI in the control group and the cochlear injury group was 40% and 0%, respectively, and for 80-90 KHz the induction rate was 20% and 20%, respectively. Gentamicin poisoning induced downregulation of expression of Prestin in cochlear outer cochlea, and Otoferlin and F-Actin in cochlear hair cells in different regions. CONCLUSIONS Gentamicin poisoning can cause different degrees of damage to cochlea hair cells in different regions. Guinea pigs with gentamicin poisoning can recognize high-frequency ultrasonic signals.
Abstract via europepmc.
Exposures
Exposure 1: Bone-conducted ultrasound to cochlea (30-35 kHz and 80-90 kHz)
Target: cochlea — “bone-conducted ultrasound via the mastoid region (cochlea)”
Device: custom-built
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 32.5, 85swept | ✓✓✓ |
| Pulse duration (ms) | 0.5 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 100 | ✓✓✓ |
| Duty cycle (%) | not reportedpulse duration × PRF gives 5% | |
| Sonication duration (s) | 20 | ✓✓✓ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | not reported | |
| In-situ pressure (kPa) | not reported | |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | not reported |
Ultrasonic vibration was generated by a triggered function generator system and delivered through an ultrasonic transducer as a sinusoidally enveloped random-phase pip of 32.5 kHz and 85.0 kHz in 0.5 ms duration; for ABR, 30-35 kHz and 80-90 kHz pulse square waves were used (pulse frequency 100 times/s). For fMRI ROI detection, bone-conducted pulsed square waves were used with acoustic stimulation for 20 s and no acoustic stimulation for 10 s, over a 20-min scan (600 repetitions). Stimulus intensity was expressed as amplifier output peak-to-peak voltage (max 20 V = 0 dB reference), not as an absolute acoustic pressure or intensity.
Flags from extraction
exposures[0].free_field— Stimulus intensity was reported only as amplifier output peak-to-peak voltage relative to a 20 V (0 dB) reference; no pressure (kPa) or intensity (W/cm2) value was given.adverse_events— Paper does not discuss adverse events or safety of the ultrasound stimulation itself (only gentamicin-induced cochlear damage, which is the disease model, not an ultrasound safety outcome).auditory_control— This study is itself about perception of ultrasound via the cochlea; the standard 'auditory confound' vocabulary does not map cleanly, so left not_reported.