Scientist know that there’s an ethical concern with animal testing and they have widely accepted the three Rs ethical principal for Replacement, Reduction and Refinement.
Reduction: reducing the number of animals in experiment. Strategy that will result in fewer number of animals used to obtain sufficient data.
Refinement: using experiment methods and techniques to minimize pain and distress to the animal.
Replacement: using methods that will avoid or replace animal use for experiments. Use cell cultures instead or whole animal.
We should consider the three Rs ethical principal and replace vertebrates with invertebrates that have a significantly lower potential for pain perception.