PARENT SESSION
1E Biologically based risk assessment and risk management
9:00 AM to 7:00 PM, Monday, 07 May 2001

(M/EH040) Ecotoxicological evaluation of 2,4-DCA using rainbow trout primary cultures: an in vitro/in vivo comparison.

Kilemade, Michael¹, Lyons-Alcantara, Maria¹, Rose, Tina², Fitzgerald, Richard², Mothersill, Carmel¹, ^{1 2}

ABSTRACT- Isolated cells that maintain the essential traits of the in vivo state during culture provide an excellent experimental approach to establish diagnostic markers such as early indicators of effect. To understand the ecotoxicological implications of the cellular response, in vitro studies on isolated cells must be integrated with in vivo studies on the whole animal. In previous work by this author the potential ecotoxicological hazards of 2,4-dichloroaniline(2,4-DCA) had been investigated in rainbow trout, Oncorhynchus mykiss primary epidermal cultures exposed in vitro. The purpose of this study was to investigate if the cellular responses evidenced from in vitro exposures to the toxicant were indicative of the whole animal response. For this purpose, juvenile rainbow trout were exposed in aquaria to 2 and 10microMolar 2,4-DCA over a period of 13 days. Control aquaria were also used. Employing the technique of primary epidermal cell culture, cell cultures were obtained in order to examine the following endpoints; induction/activation of heat shock protein 70 (HSP70) and the proliferating cell nuclear antigen (PCNA) and also the growth rate of the proliferating epidermal cells. HSP70 levels increased and PCNA levels decreased, as did the growth rate of the proliferating epidermal cells. All three endpoints responded in a dose-dependent manner. These findings mirrored the in vitro exposure situation The results of this in vivo exposure study validate those obtained from the in vitro exposures and demonstrate that trout primary epidermal cultures retain the characteristics of the in vivo condition of the animal from which they are obtained. This finding has valuable implications for environmental risk assessment.

Key words: rainbow trout, primary cultures, risk assessment, in vitro/in vivo