Related Experiment Video
Updated: Apr 6, 2026
Cochlear Implant Surgery and Electrically-evoked Auditory Brainstem Response Recordings in C57BL/6 Mice
Published on: January 9, 2019
Pathological changes of cochlear in deaf mice at different time after mouse cytomegalovirus infection
Yongyuan Tian1, Xinguo Liu1, Hongjian Liu1
1Department of Ear-Norse-Throat, The Zhumadian City Center Hospital No. 747 Zhonghua Road, Zhumadian 463000, P. R. China.
Objective:
This study aims to observe the pathological changes of inner ear in deaf mice at different time after mouse cytomegalovirus infection.
Methods:
A total of 60 BALB/C mice were divided into 2 groups randomly: model group (A) and control group (B). In model group, 10 μl of MCMV was injected into the brain of each mouse while 10 μl of physiological saline was injected in control group. 10 cochlear samples were taken from 5 mice selected from each group randomly after infection for 1, 3, 5, 7, 14 and 21 days respectively. They were detected with PCR and HE staining methods. Auditory brain stem response was determined. The apoptosis of spiral ganglion (SGN) cells was detected by apoptosis assay kit. The levels of Bcl-2 and Bax were detected by RT-PCR and western blotting methods.
Results:
In group A, PCR results were negative after infection for 1 day, they were positive after infection for 3 days to 21 days. In group B, PCR results were negative in the experimental period. Compared with group B, ABR I wave latency and threshold increased while ABR I wave decreased in group A. There were no obvious hyperemia and inflammatory cells infiltration in group B, In group A, hemorrhage of scala tympani and scala vestibule appeared and reached highest peak after infection for 3 days accompanied by inflammatory cell infiltration; the vestibular membrane thickened after infection for 5 days; cell gap of SGN cells widened, arranged more sparsely with cell edema after infection for 7 days accompanied by infiltration of plasma cells; fibroblast proliferation and fibrosis appeared after infection for 14 days.
Conclusions:
MCMV infection occurred in cochlear after MCMV infection for 3 days and could sustain, the continues pathological changes of inner will bring difficulties to the treatment of CMV deafness, further studies on the specific mechanism of SGN changes caused by CMV infection will provide an important target for the treatment of CMV deafness.
Insights
Mouse cytomegalovirus (MCMV) infection causes progressive inner ear pathological changes, including spiral ganglion cell apoptosis, leading to hearing loss. These findings highlight challenges in treating CMV-induced deafness.
Area of Science:
- Otolaryngology
- Virology
- Pathology
Background:
- Mouse cytomegalovirus (MCMV) is a known pathogen with potential ototoxic effects.
- Understanding the temporal progression of MCMV-induced inner ear pathology is crucial for developing effective treatments for hearing loss.
Purpose of the Study:
- To investigate the pathological changes in the inner ear of mice following MCMV infection.
- To correlate these changes with auditory function and cellular apoptosis over time.
Main Methods:
- BALB/C mice were infected with MCMV or saline (control).
- Cochlear tissues were analyzed using PCR, HE staining, and apoptosis assays.
- Auditory brainstem response (ABR), Bcl-2, and Bax levels were assessed.
Main Results:
- MCMV was detected in cochlear tissues from day 3 post-infection.
- Infected mice showed increased ABR latency/threshold and decreased ABR wave I amplitude.
- Pathological changes included hemorrhage, inflammation, vestibular membrane thickening, spiral ganglion cell edema, and fibrosis.
Conclusions:
- MCMV infection establishes in the cochlea by day 3 and persists, causing sustained inner ear damage.
- The observed pathological changes, particularly in spiral ganglion cells, present significant challenges for treating CMV-induced deafness.
- Further research into the mechanisms of SGN changes is vital for identifying therapeutic targets.
