Abstract
Purpose :
To examine the effects of the fungal toxin Aflatoxin B1 (AFB1) on visual function in zebrafish larvae. AFB1 is a powerful mutagen and carcinogen produced by molds of the genus Aspergillus that produces reactive oxygen species (ROS) and can grow on food items after harvest. Our hypothesis is co-exposure with an antioxidant like ellagic acid (EA) will mitigate the deleterious effects of AFB1 on the visual system.
Methods :
Zebrafish larvae (N=15-20 per treatment) were co-exposed to AFB1 (0.14 μg/mL) and low (1.7 μg/mL), medium (3.4 μg/mL), or high (6.8 μg/mL) dosages of EA for one of two 48-hour periods during either 0-48 or 24-72 hours post fertilization (hpf). Control groups included system water, AFB1 vehicle (methanol), EA vehicle (NaOH neutralized with HCl) and EA at three dosages without AFB1. Visual function was determined behaviorally by an optokinetic response (OKR) at 5 days post fertilization. OKR responses were compared among treatment groups via ANOVA and a post hoc multiple comparisons test.
Results :
OKR did not vary significantly across treatment group in larvae treated during the 0-48 hpf exposure window. However, larvae treated with AFB1 during the 24-72 hpf window displayed a significantly decreased OKR compared to water controls. Co-exposure with EA showed a trend of increasing OKR responses from low to medium to high dosages of EA, but values were not significantly greater than AFB1 and were significantly depressed below those of the water control. EA applied alone significantly decreased the OKR response compared to water controls at low doses; whereas the medium and high dosages were not different from the water control.
Conclusions :
Though significant mitigation of the negative effects of AFB1 by EA were not seen, trends noted in the 24-72 hpf exposure window suggest that ROS effects of AFB1 might be greater during the later phases of visual development (i.e., exposure starting at 24hpf) than during early phases (i.e., exposure starting immediately after fertilization).
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.