Neuro-2a cell-based assay for toxicity equivalency factor - proposal and evaluation in Chilean contaminated shellfish samples

ABSTRACT

There are two official PSP detection methods (mouse bioassay and HLPC-FLD) and a number of alternative methods. Ethical considerations have led to regulations being adopted in some countries that limit or prohibit the application of mouse bioassay. Analytical methodologies (e.g. HPLC-FLD or LC-MSMS) have the disadvantages of not being able to detect new toxins or analogues or reflecting the overall toxicity of the sample. In addition, they require highly trained personnel and expensive equipment, which are not always available. In this work, we have evaluated a method based on the Neuro-2a cell-based assay to detect substances that inhibit voltage-dependent sodium channels (Manger’s method). We tested PSP standards and natural samples contaminated with PSP. Here we demonstrate that the adapted Manger’s method is suitable for calculating Toxicity Equivalency Factors (TEF) for STX-analogues. The method was shown to be useful for screening contaminated natural samples in concentrations above the regulatory limit for these toxins (80 μg STX equivalents/100 g shellfish). We were able to detect PSP in 19 natural mollusc samples from South Chile despite the presence of other marine toxins. These preliminary results suggest that the method could be used as a first step in screening programmes.

KEYWORDS:

• Neuro-2a cell-based assay
• toxicity equivalency factor
• shellfish
• PSP

Acknowledgments

The authors acknowledge Dr. Jorge Diógene from the IRTA (Spain) and Gore BioBio FIC-R 40000139 for providing support. This research was funded by the projects: Fondecyt 1170515 (Conicyt, Chile) and Innovation Fund for Regional Competitiveness (FIC-R 4000139; Regional Government of Biobío, Chile). We also thank the Public Health Institute (Ministry of Health, Chile) and the Universidad de Concepción for their support (VDRI-ENLACE project 217.114.003-1.0).

Additional information

Funding

This work was supported by the CONICYT-FONDECYT [1170515]; VRID- enlace project Universidad de Concepción [217.114.003-1.0]; Fondo de Innovacion para la competitividad Regional [GORE BIOBIO FIC-R 40000139].