The Center for Alternatives to Animal Testing is an academic center affiliated with the Division of Toxicological Sciences in the Department of Environmental Health Sciences of the Johns Hopkins University Bloomberg School of Public Health.

 

Johns Hopkins School of Public Health

Research Grants 2008-2009

The “mini-mouse” toxin detection assay

Dr JE Dalziel, PhD
Ag Research

The project will use the voltage-gated sodium ion channel (VGSC) from human skeletal muscle to test the safety of potentially contaminated shellfish and drinking water for human consumption. When the algal toxins brevetoxin and saxitoxin bind to VGSCs they disrupt normal nerve and muscle function and can produce poisoning neurological effects that range from irritated nasal passages and coughing, to ataxia and paralysis. Shellfish biotoxins require routine monitoring worldwide to protect public health. Currently the main internationally validated biological based method to measure the toxicity of these compounds is the mouse bioassay. This has been deemed outdated by the World Health Organisation for both scientific and ethical reasons. The aim of this research is to develop the “mini-mouse” assay as a method to reduce the numbers of laboratory mice required to carry out LD50s to test the neurotoxicity of algal toxins in contaminated shellfish. The electrophysiological assay that we have developed consists of a bilayer lipid membrane supported by porous Teflon that is preloaded with VGSC protein incorporated into liposomes. We will investigate the ability of this assay to determine the concentration of brevetoxins (activators) and saxitoxins (inhibitors). By using a natural biological target for saxitoxin, this in vitro assay will recognise this dangerous toxin and other isomers that might arise. The proposed mini-mouse assay has the potential to contain a suite of different ion channel receptors against which a range of potentially harmful shellfish toxins are active.