BIS-(3-ALLYL-4-HYDROXYPHENYL) SULFONE (TGSH) DECREASES EMBRYONIC VIABILITY AND ALTERS HEPATIC mRNA EXPRESSION AT TWO DISTINCT DEVELOPMENTAL STAGES IN CHICKEN EMBRYOS EXPOSED VIA EGG INJECTION

Abstract

Concerns surrounding the toxicological effects and environmental prevalence of bisphenol A (BPA) have increased efforts to identify suitable, safer replacement alternatives. Bis-(3-allyl-4-hydroxyphenyl) sulfone (TGSH) represents a potential BPA alternative; however, exposure and ecotoxicological data are scarce. TGSH was injected into the air cell of unincubated, fertilized chicken embryos at 4 concentrations ranging from 0 to 180 μg/g egg to determine effects on embryonic viability, development, and hepatic mRNA expression at two distinct developmental periods: mid-incubation (day 11) and pipping (day 20-21). TGSH concentrations increased in a dose-dependent manner in whole embryo homogenates and the estimated median lethal dose based on embryonic viability at mid-incubation was 66μg/g (95% confidence interval=31-142μg/g); similar to the BPA LD50 (∼67 μg/g) reported in a previous study. Modulation of hepatic gene targets from a chicken ToxChip polymerase chain reaction array was observed at both developmental stages. At mid-incubation, 21/43 genes on the PCR array were significantly altered (>1.5-fold) in the 180 μg/g dose group, while 9 and 6/43 were altered at pipping in the 9.2 and 48 μg/g groups, respectively. Predominant toxicity pathways included xenobiotic metabolism, lipid homeostasis, bile acid synthesis, and cell cycle regulation. The estrogen-responsive gene, apolipoprotein II, was significantly up-regulated in liver tissue of mid-incubation embryos at 180 μg/g; however, neither apolipoprotein II nor vitellogenin II were altered at the other concentrations or developmental time points. Given the importance of identifying suitable BPA replacement alternatives, the present study provides novel, whole animal toxicological data for a BPA replacement alternative that has a similar effect on embryonic viability as the compound it could replace. This article is protected by copyright. All rights reserved

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