Revuelta, M. 1 , Arteaga, O. 1 , Montalvo, H. 1 , Álvarez, A. . 1 , Martinez-Ibargüen, A. 2 & Hilario, E. 1
1 Dept. Cell Biology & Histology, School of Medicine & Dentistry, University of the Basque Country, Leioa, Bizkaia, Spain.
2 Dept Otorhinolaryngology,School of Medicine & Dentistry, University of the Basque Country, Leioa, Bizkaia, Spain
Maturation of the auditory pathway is related to central nervous system myelinization and can be affected by pathologies such as neonatal hypoxic-ischemic encephalopathy. To evaluate the auditory capacity in newborns, it is commonly used the auditory evocated potentials (AEPs).
Our objective is to determinate the functional integrity of the auditory pathway and to visualize the damage in the brainstem using a model of hypoxic-ischemic (HI) brain injury in neonatal rats.
7-day-Sprague-Dawley rats were randomly assigned to the SHAM groups (no ischemic or hypoxic injury) and the HI groups (permanent left carotid occlusion and reduction of 02 to 8%) by Rice-Vannucci method. The AEPs were measured at 14 days and animals were sacrificed and the brainstem isolated, paraformaldehyde fixed, paraffin included, sectioned and stained with hypoxiprobe kit.
The Auditory Pathway was altered during the hypoxic-ischemic insult, with an increase in the latency of the I-V and III-V waves? ratio.
At histological level, the hypoxiprobe kit stained cells exposure to a reduction of the oxygen, so we observe in the HI group a different staining comparing to the SHAM. Besides, we observe a difference in the morphology of the brainstem in the left side comparing to the SHAM group owing to the ischemic event.
Our results suggest that the HI event reduces the auditory capacity and generate neuronal damage in the brainstem.