Mice that regenerate toes, internal organs, "anything but the brain".
Mice that live 19 to 31 % longer than expected.
The cliche about mouse studies is that we can do just about anything to rodents that we want. We can yank their lifespan around, double their muscle mass, give them wings, cure all kinds of cancer; trying to do the same things in humans is almost always less successful, for reasons that are not always clear. For example, numerous studies have shown that calorie deprivation extends the lifespan of rats & mice. One reason for this may be that standard rat chow isn't very healthy, rather than the hypothesized reason that calorie restriction either a) adjusts the animals' metabolic rate or b) changes gene expression. On the other hand, the calorie restriction experiments could also reasonably point to the insulin-like growth factor receptor cascades which are controlled by the life-extension experiment described above.
Feeling extropian, anyone?