Observation of permeability of blood–labyrinth barrier during cytomegalovirus-induced hearing loss

ObjectiveCongenital cytomegalovirus (CMV) infection is the most common infectious cause of sensorineural hearing loss in children. This study aims to investigate the pathogenesis CMV-induced hearing loss from the view of integrity of blood–labyrinth-barrier (BLB).MethodsNewborn BALB/c mice were randomly divided into three groups (n = 22, respectively): CMV group, control group and normal group. The CMV group and control group were intracerebrally injected with equal volume (15 μl) of murine CMV (MCMV; 104 IU/0.1 ml) and PBS, respectively, and normal group did not receive any treatment. After three weeks, auditory-evoked brainstem response was assessed, and permeability of BLB was evaluated by Evans blue method. Means between groups were compared using t-test.ResultsWe observed that mice injected with MCMV had a hearing loss and it was connected with the permeability changes of BLB. Besides, using hematoxylin–eosin staining, we noticed hyperaemia in stria vascularis and spiral ligament and bleeding in scala vestibule and scala tympani in CMV group.ConclusionAll these data indicated the possible association between CMV-induced hearing loss and BLB dysfunction with the characteristics of inflammation. Our data provide a possible path to investigate the mechanism of CMV-induced hearing damage.