PM10 Mechanisms of Toxic Action
Exhibit Hall
8:00 AM - Monday
(PM159) Does co-exposure to phenanthrenequinone modify the impact of copper on cellular stress response in rainbow trout gills?
Weil, R1, Vijayan, M1, 1 University of Waterloo, Waterloo, Ontario, Canada
ABSTRACT- Heavy metals and photomodified polycyclic aromatic hydrocarbons (PAHs) are often found as co-contaminants in aquatic environments. Traditional toxicological studies have focused on PAHs, but little is known about the potential hazards of the photomodified forms of PAHs. Independently, both heavy metals, such as copper, and photomodified PAHs have been shown to be toxic to aquatic organisms, but very little is known about the mechanisms underlying their co-toxicity in fish. Using gill filaments as an in vitro model system, we are characterizing the impact of co-exposure to copper and phenanthrenequinone (photomodified PAH) on cellular stress response and gill function in rainbow trout (Oncorhynchus mykiss). To this end, gill filaments were treated with CuSO4 (0-500 
M) for 4 and 24 h and heat shock protein 70 (hsp70), metallothionein and glucocorticoid receptor (GR) protein expression were used as indicators of cellular stress response. Copper exposure induced a cellular stress response as evidenced by an increase in hsp70 and GR protein expression. Also, high copper concentration inhibited gill Na+/K+-ATPase, and glutathione peroxidase activities over a 24 h period. However, the activity of glutathione reductase was not altered by copper treatment. Studies are underway to examine whether this copper-mediated cellular stress response is modified in the presence of the photomodified PAH. Overall, these studies are geared towards elucidating the mechanism(s) of action of contaminant mixtures on gill function in trout. Support for this study was provided by the Natural Sciences and Engineering Research Council (NSERC), Canada, Strategic grant
Key words: phenanthrenequinone, copper, co-toxicity, fish