UC Riverside

Triphenyl phosphate (TPHP) is an organophosphate ester-based plasticizer and flame retardant that is used worldwide and detected at elevated levels within environmental media such as surface water, dust, and sediments. Past studies have found that TPHP causes adverse phenotypes within embryonic zebrafish when exposed from 24-72 h post fertilization (hpf), including prevention of cardiac looping due to pericardial edema. TPHP is not the only environmental contaminant that is known to cause pericardial edema in embryonic zebrafish, as over 35 other chemicals have been found to cause pericardial edema. However, little is known about the mechanism leading to edema formation within fish embryos even though there are numerous studies that have investigated the mechanisms underlying edema within mammalian models and humans. In Chapter 2, we will determine whether TPHP exposure disrupts the abundance of Na+/K+ ionocytes in early embryonic development within zebrafish. In Chapter 3, we will determine whether media ionic strength affects the toxicity of TPHP within embryonic zebrafish, including potential impacts on the yolk sac epithelium. In Chapter 4, we will determine how TPHP induces injury to the yolk sac epithelium by focusing on potential effects on prolactin abundance and wound repair, as well as whether TPHP-induced pericardial edema is reversible or irreversible. Overall, using TPHP as a reference chemical, we expect our findings will increase our understanding of mechanisms underlying chemically-induced edema formation within embryonic zebrafish.