I feel like I can see two sides here:
- The mouse was genetically manipulated (heavily). It’s been created explicitly for this sort of work. Up until this procedure, they lived (I’d argue) pretty good lives for mice- warm, dry, fed, watered, clean… And the animals are expensive. I’m not sure of the strain/age/gender being used here, but it’s pretty easy for research mice to be north of $100 each, so there’s even more incentive for researchers to get the procedures right and maximize the animals’ life.
- The upside of the research is huge. I’m no fan of animals suffering, but what ratio do we keep for the number of mice dying that we’re ok with as compared to the humans it will eventually help?
Look, I clearly don’t have answers here- but in my time with people who do animal research, they’re no sadists. There’s just no other way to get the information they need.