Scanning electron microscopy of cochlea in new-born rats exposed to hyperbaric oxygen: preliminary report

The aetiology of hearing loss in new-borns in neonatal intensive care is still debated. While the physiopathology of brain, lung and retina damage related to oxygen supplementation has been widely described, no studies have been carried out to define the relationship between hearing loss and supplementation of oxygen in new-borns. In the present investigation, the cochlear morphology of new-born rats was evaluated by means of scanning electron microscopy in order to assess morphological changes after supplemental oxygen administration. After treatment, electron microscopy revealed many changes in the morphology of outer hair cells, if compared to normal rats of the same age. The results suggest that cochlear changes are similar to those previously observed in other regions and may be related to a vascular mechanism of hypoxia-ischaemia and neovascularization and/or an oxidative stress.