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Carlos A Garcia, Jordan M Wetz, Apeameokhai Philip Aitsebaomo; Scotopic electroretinogram a- and b-wave alterations in adult rats after an acute exposure to ozone. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5340.
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© ARVO (1962-2015); The Authors (2016-present)
Millions of people who suffer from retinal disease live in air polluted environments. The impact of the gaseous air pollutant ozone (O3), a strong oxidant, on the retina is unknown. The purpose of this study is to compare the electroretinographic responses between control and O3 -exposed rats and to better understand the effect of O3 on retinal function.
Age- and sex-matched Long Evans rats were randomly separated into two groups (n=12 rats); six control (clean air) and six acute O3-exposed (0.4 ppm for 4 hours). Full-field electroretinography (ERG) was recorded simultaneously from both eyes in each rat. The scotopic ERG, a-wave, b-wave, and photopic negative response (PhNR) was measured and compared between the two groups. Recordings were performed under general anesthesia (ketamine 70 mg/kg, xylazine 2.5 mg/kg, IP). Active corneal electrodes were designed for use in rats. A ground needle electrode was placed subcutaneously in the real flank of the animal. Pupils were dilated with 2.5% phenylephrine and 1% tropicamide eye drops. Lubrication and proper electrical conductance of the active electrode were maintained with Refresh lubricant eye drops. Rats were dark adapted for 30 minutes before scotopic responses were measured.
Experimental data indicates, in the scotopic ERG, an acute exposure to O3 significantly (p < 0.05) decreased the a-wave amplitude at intensities raging from -0.001 to 25 cd.s/m2. The trough of the a-wave decreased by a mean of 11 mV. The amplitudes of the b-waves were significantly higher (p < 0.01) by 7.72 mV in the O3 –exposed rats across all tested stimulation intensities. No mean significant change was observed in the photopic negative-response (PhNR) between the control and exposed groups.
This work demonstrates O3 exposure leads to alterations in the rod system as indicated by the scotopic ERG changes. Results suggest air pollution may contribute to retinal deficits in sensitive populations living in air-polluted environments. It also provides useful data in establishing air quality standards to better protect the populations living in air polluted areas to prevent the possible O3–induced oxidative stress that may contribute to retinal neuron dysfunction.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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