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Scientific progress

07 - 02 - 2017

Butterfly larvae to replace mammals in toxicity tests?

Scientists working on moth larvae have received funding to determine whether this animal model can be used instead of mammals for toxicity studies of new therapeutic molecules.  Details bellow.

Butterfly larvae to replace mammals in toxicity tests?

Over the past two years, scientists at the University of Exeter (UK) have been working on the worm moth larvae (Galleria mellonella), an interesting animal model, inexpensive and effective to carry out toxicological tests. They founded BioSystems Technologies Ltd, a start-up company whose main objective is to supply researchers with wax moth larvae to assimilate this new model.


Seduced by the idea of possibly replacing mammals with these larvae in toxicity studies for new therapeutic molecules, the NC3Rs, the National Center for Replacement, Refinement and Reduction of Animals in Research (the famous 3Rs rule) has just awarded them two grants of £ 12,000 (about € 13,900). The first fellowship will be a partnership with the clinical research company Envigo to determine whether this species can actually contribute to reducing or even replacing the number of mammals used in toxicity testing. The second scholarship will support a partnership with the antibiotic discovering company Demuris to find out if the larvae of this butterfly can be a safe and effective way to test compounds in the search for new antibiotics.


The need for more regulated supply


Already used to study microbial infections and to select for effective antimicrobials, this model remained limited to academia, and has never been used in private laboratories. The reason is simple: the lack of a secure and constant supply of these larvae, has led to significant variations between the different batches produced. "People literally bought these larvae from bait stores," says Dr. Olivia Champion, co-founder of BioSystems Technologies Ltd. with Professor Richard Titball. "Even scientists at the best research institutions here and abroad were doing this, and the differences between the larvae resulted in unacceptable levels of variability in the results." BioSystems Technologies Ltd is therefore working to solve this problem by offering wax moth Larvae under the trademark TruLarv.


Reduce if unable to replace


For both scientists, enthusiastic about these moth larvae, the idea is to test some therapeutic molecules on this model before going on to mammalian tests. These larvae would therefore be an intermediate step between in vitro studies (on cell models) and in vivo studies on vertebrates and / or mammals. Enough to do a first selection among the samples of molecules, according to their toxicity, rather than to test them directly on a mammal like mouse, rat etc. In a nutshell, this is what is currently being done in zebrafish, which is an attractive model because it is easily bred and has a relatively low cost. But it took years to convince researchers of the use of this model so it could enter laboratories. However, tests on mammals remain inevitable, because butterfly larvae and zebrafish are not close enough to humans at the functional and organizational level. But this may be an interesting approach to decrease the number of studies on mammals, which corresponds to the reduction R of the 3Rs rule.


Hélène Bour


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