Pathological changes of the inner ear cochlea in different time windows of murine cytomegalovirus-induced hearing loss in a mouse model.

Conclusions: Murine congenital cytomegalovirus (CMV) (MCMV) infection of the inner ear cochlea, which caused continuous pathological change, occurred on the third day after intracerebral injection and persisted for a very long time.

Objective: Our study used the MCMV-induced hearing loss neonatal mouse model to investigate the pathological changes of the cochlea in different time windows.

Methods: Sixty newborn BALB/c mice were randomly and equally divided into the experimental group (MCMV intracerebral injection) and control group (normal saline intracerebral injection). At 1, 3, 5, 7, and 21 days after intracerebral injection, cochleas were extracted and evaluated by MCMV-DNA PCR analysis and histopathological examination.

Results: Two mice died before the end of the experiment in the experimental group, while there were no deaths in the control group. In the experimental group, the MCMV-DNA PCR samples did not show positive results in the gel electrophoresis until the 3-21 days after intracerebral injection, while no positive result was found in the control group. Pathological changes including hemorrhage and inflammatory cell infiltration of the scala vestibule and scala tympani began on the third day, spiral ganglion cell gap widening and cell thinning began on the seventh day, and scala tympani fibrosis began on the 14th day.