[algorias]

Presumably, the eventual goal is to grow full-sized organs inside some larger animal. Then the organ can be harvested and transplanted to a human who needs it. Per my understanding, medicine does a lot of work with rats because they're cheap and easy to work with, so any new technology of this type would be tried on rats first.

By the way, my neutral explanation above doesn't mean that I approve of doing such things. Honestly, I'm quite torn about the issue.

[noir_lord]

I'm not remotely torn about it, taken to the finish, it's a human organ with my dna grown in a pig and then transplanted into me.

We already eat bacon and use large mammal heart valves in surgery.

I mean we wear the skin of cows, grease things with their rendered fat and use them for glue.

This seems like a strange point to be torn on.

[mrfusion]

Remember that a bio ethicist has years of education on smart ways to block stuff like this.

If they didn’t block this stuff they wouldn’t have a job.

[algorias]

Well, "we" don't all eat bacon and wear the skin of cows. What's strange about wanting to respect other living beings and avoid harming them? This is also not incompatible with the belief that a human life should come first, e.g. in your heart valve example.

[oneshot908]

I quite enjoyed the cognitive dissonance of the PETA director being a Type 1 Diabetic.

https://www.humanewatch.org/person/mary_beth_sweetland/

[toomuchtodo]

Hopefully the use of animals for tissue incubation and harvesting is a bridge to a future when animals are no longer required for human tissue synthesis.

Artificial womb experiments are going well [1], as well as tissue synthesis for cultured meat (which is just animal muscle), so...maybe?

[1] https://www.theverge.com/2017/4/25/15421734/artificial-womb-...

[NewsAware]

Reminds me of the Bene Tleilax and their Axlotl tanks - presumed to be advanced technology but in reality female humans.

[HillaryBriss]

> when animals are no longer required

maybe an impossible burger?

[tombert]

I don't know about Japan, but in the US rats are also often used because they're basically the biggest mammal that has almost no regulation on what you do to them. Experimenting on, for example, a monkey might be closer to something human, but they're not legally classified as pests, so doing things with them requires a lot more paperwork and might not be approved.

Definitely not saying it shouldn't be that way; I'm kind of glad that we have some level of ethical rules for handling animals.

[magduf]

You're missing one of the other huge factors in why mice and rats are used for experiments: lifetime. These animals (esp. mice) have very, very short lifetimes by human standards, so you don't have to wait around for decades to see how something affects the animal over its whole lifespan. This is especially useful for aging research: it doesn't take very long for mice to become "elderly", so you can test out anti-aging experiments on them. Doing this on humans, even if it were totally legal, would be very slow because it'll take you 70+ years to grow a human in a lab to old age. Mice can only live a few years at most.

[tombert]

Yeah, and unlike something like a fruit fly, which also has a short lifespan, mice are mammals, so they are still fairly close to us in the animal kingdom, relatively speaking.