Abstract
Purpose :
Electroretinography assesses retinal function as a safety endpoint in nonclinical studies. As defined by ISCEV, the five basic responses considered of value are rod response, rod-cone maximal response, oscillatory potentials, cone response, and response to a flickering stimulus. Changes in body temperature may affect the ERG responses, particularly in small laboratory animals. Changes in oxygen saturation have been shown to affect the ERG response in humans. This study evaluated whether changes in body temperature and/or oxygen saturation, as well as duration of sedation, affected waveform amplitude or latency of ERG response in macaques.
Methods :
Thirty-two Mauritius cynomolgus monkeys were evaluated for baseline ERG responses. ERGs were conducted in accordance with ISCEV standards. Animals were sedated with ketamine and placed on a draped table surface. Mechanisms to control body temperature and oxygenation were not used. Baseline temperature and oxygen saturation readings were taken prior to the administration of dexmedetomidine. Temperature and oxygen saturation readings were collected prior to the scotopic cone ERG and at the end of the ERG procedure.
Results :
No single animal had the lowest ERG amplitudes or longest latency for the 5 assessed parameters. One animal had the highest amplitude for rod (OD), maximal (OU), and OP, cone and flicker (OS). Temperature and oxygen saturation for this animal were at or near the average values for all animals. The longest duration of sedation was 35 minutes, which corresponded with the lowest amplitude for rod, maximal, and OP, but only in the left eye; as well as the longest latency for the initial flicker response in both eyes. However, similar findings were not noted for several animals with elapsed time of 25-30 minutes. Minimum amplitudes and latencies were fairly evenly distributed amongst male and female animals. The majority of the maximum amplitudes and latencies were noted for male animals.
Conclusions :
The procedures used in this evaluation did not appear to adversely impact ERG amplitude or latency; however, development of an efficient process for sedation and data collection is warranted.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.