Effects of Intrauterine and Extrauterine GSM-like Radiofrequency on Distortion Product Otoacoustic Emissions in Infant Female Rabbits

Abstract

Objective: We investigated the effects of 1,800 MHz GSM-like Radiofrequency (RF) on the cochlear functions of female infant rabbits by Distortion Product Otoacoustic Emission (DPOAE) recordings upon intrauterine (IU) and/or extrauterine (EU) exposure. Materials and Methods: Thirty-six infant female New Zealand White rabbits, each one-month-old, were randomly divided into four groups, Groups 1-4, each having 9 rabbits. Group 1 animals were remained untreated (Control), whereas other groups were treated by virtue of extrauterine (Group 2, EU), intrauterine (Group 3, IU), or both type of exposure (Group 4, IU and EU) to 1800 MHz GSM-like Radiofrequency (RF). EU exposure started after they reached to one-month of age, and IU was at intrauterine period which was in between 15th to 22nd days of gestation. The duration for exposures was 7 days with 15 minutes per day protocol. Cochlear functions were assessed by DPOAEs at 1.0-8.0 kHz. Results: DPOAE amplitudes for EU-RF group at 1.0 and 1.5 kHz was found higher with respect to control. At 2.0 kHz, the recordings for EU-RF group were higher than control and IU-RF groups. At 6.0 kHz, EU-RF group were higher than control, IU-RF, and (IU+EU)-RF groups. At 8.0 kHz, EU-RF group were higher than IU-RF and (IU+EU)-RF groups. Conclusions: We conclude that if the anatomical growth of exposed animate is completed and the extrauterine GSM-like RF exposure is not prolonged, there will not be much harmful effects on inner ear of female rabbits, measured by DPOAEs. The observed increase in DPOAE amplitudes at 1.0-2.0 kHz shows the increase in cochlear activity and outer hair cell electromotility. Prolonged exposure and hyperthermia related to the power density of applied RFR, increasing the temperature in the ear canal, may affect the DPOAE amplitudes especially during intrauterine period. When pregnant women use earphone or even carry their mobile phones in their bags or pockets, foetus may expose to GSM-like RF from the very short distance with the exposure level higher than the standard limits, which may cause ear toxicity with decreased DPOAEs.