Botulinum neurotoxin: from the lethal mouse test to cell-based laboratory models
This study examines why mice continue to be used in severe LD50 tests for the quality control of botulinum neurotoxin (Botox), even though reliable animal-free cell-based assays are now available. In the traditional LD50 test, mice receive different doses of the toxin to determine the dose at which 50% of the animals die. During the test, they may develop paralysis and respiratory distress before dying, and a single assay can use around 100 mice. Available data indicate that more than 100,000 mice are used each year in Ireland, the United Kingdom, and Germany combined for regulatory potency testing of pharmaceuticals, including botulinum neurotoxin LD50 tests. The exact number of animals used specifically for botulinum neurotoxin remains unclear due to insufficient public reporting. However, project documentation suggests that substantial use has continued, particularly in Ireland and the United Kingdom. In Germany, by contrast, mouse testing for botulinum neurotoxin appears to have been largely phased out. The authors call for greater transparency and a rapid, mandatory transition to modern animal-free cell-based assays to ensure that the harmful LD50 mouse test is completely replaced.
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