Effect of Ganciclovir on murine cytomegalovirus-induced hearing loss in a mouse model

We evaluated the effect of Ganciclovir on murine cytomegalovirus (MCMV)-induced hearing impairment in a mouse model by studying modulations in auditory brainstem response (ABR) and pathological changes in the inner ear. MCMV infection was established via trans-brain. For this purpose, 24 BALB/c newborn mice were randomly and equally divided into control group (10 μl of sterile normal saline was injected); model group (10 μl of MCMV TCID50-10(4) IU/0.1 ml was injected); and interfered group (Trans-brain MCMV; Ganciclovir at the rate of 60 mg/kg was intraperitoneally injected). ABR audiometry was performed after 14 days. Acoustic vesicles were obtained for MCMV-PCR analysis and histopathological examination. Comparing ABR in model group against controls, incubation period of wave was lengthened (F = 9.151, P = 0.011-0.05) and wave amplitude was cut down (F = 5.095, P = 0.043-0.05). Comparing ABR in model group against interfered group, incubation period and amplitude of wave were F = 13.797 (P = 0.003-0.05) and F = 14.587 (P = 0.002-0.05), respectively. Cochlear histopathological changes in model group included thickening of vestibular membrane, lymphocytic infiltration, and fibrous degeneration of cochlear duct. In Ganciclovir interfered group, however, these pathologic changes were less significant as compared with those of model group. We, therefore, conclude that Ganciclovir treatment at the early stage of MCMV-induced hearing impairment inhibits the disease progression in infected mice.