Evaluation of Jet Fuel Induced Hearing Loss in Rats
Final rept. 3 Jan-6 Sep 2011
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH HUMAN PERFORMANCE WING (711TH)
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The objective of the current work was to evaluate the potency of JP-8 jet fuel to enhance noise-induced hearing loss NIHL using inhalation exposure to fuel and simultaneous exposure to either continuous or intermittent noise exposure over a 28 day exposure period using both male and female Fischer 344 rats. In the initial study, male n5 and female n5 rats received inhalation exposure to JP-8 fuel for 6 hrday, 5 daysweek for 28 days at doses of 200 mgm3, 750 mgm3, and 1500 mgm3. Parallel groups of rats also received non-damaging noise constant octave band noise at 85 dBlin in combination with the fuel, noise alone 75, 85, and 95 dB, fuel alone 200 mgm3, 750 200 mgm3, and 1500 mgm3 , or no exposure to fuel or noise. Significant dose related impairment of auditory function measured by distortion product otoacoustic emissions DPOAE and compound action potential CAP threshold was seen in rats exposed to combined JP-8 plus noise exposure when JP-8 levels of 1500 mgm3 were presented with trends toward impairment seen with 750 mgm3 JP-8 Noise . JP-8 alone had no effect on auditory function. In a subsequent study, male n5 and female n5 rats received 1000 mgm3 JP-8 for 6 hrday 5 daysweek for 28 days with and without exposure to 102 dB octave band noise that was present for 15 min out of each hour total noise duration 90 min. Comparisons were made to rats receiving only JP-8, only noise, and those receiving no experimental treatment. Pronounced impairment of auditory thresholds especially for high frequency tones were identified in the male rats receiving combined treatment.
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