Hearing outcome of early postnatal exposure to hypoxia in Sprague–Dawley rats

Abstract

AbstractObjective:To determine the effect of experimentally induced hypoxia, in the first 10 days of life, on physiological hearing in a Sprague–Dawley rat model.Methods:A prospective, controlled animal study was carried out using 22 male rat pups. The rats in the hypoxic group (n = 12) were reared in hypoxia for the first 10 days of life, and subsequently reared in normoxia, while those in the control group (n = 10) were reared in normoxia for the duration of the experiment. Hearing was assessed using auditory brainstem response testing at approximately 72 days of age.Results:The hypoxia group had higher auditory brainstem response thresholds for all frequencies tested (more pronounced at 16 kHz), compared with controls. Wave I–V inter-peak latencies were more prolonged in the hypoxic rats, while both groups had similar wave I latencies.Conclusion:Chronic postnatal hypoxia induced permanent hearing loss in this Sprague–Dawley rat model. Prolonged wave I–V inter-peak latencies suggested functional abnormality in the central auditory pathway.