They do these kinds of studies on mice because mice have a high homology with humans, and a huge number of the findings extrapolate to humans.

Yes, and as a model organism they're fantastic. But I feel any and all studies on mice need to have "on mice" always in any published study or news report about that study.

But it's one thing to pump a 100g/100g of micro plastics to bodyweight directly into the brain of a mouse and another to study mice in a mostly natural environment filled with plastic dust in similar proportions to what we find in our human lives..

Reminds me of those "mobile phone radiation is bad for you" studies. I read a few and calculated the energy they exposed those mice with in joules per kg, and it was like putting your head in a microwave oven for a few seconds. No wonder the mice had some issues afterwards...

Exactly, thank you.

I mean, I can understand doing those kinda of experiments in animals since it would be unethical to do them in humans (not going to discuss the implications of doing tests in animals either, let's just say that doing them in animals is less controversial). But as always the title omits this crucial point of information, mostly probably because this generate more clicks for the website, but I hate this trend so much.

Any idea what percentage of mice studies do extrapolate to humans?

That's a great question and thesis statement. I look forward to hearing the results from someone spending 4 years of their lives researching the answer.