There have been a few articles on the radio and in the news lately about people protesting for and against the use of animals in scientific research.
Certainly there are ethical considerations when using any live organism in research, and experiments that should never be undertaken because they subject animals to extreme and cruel situations that do nothing to further essential scientific research that will, in the end, advance in some significant way scientific knowledge. This research must, for example, improve understanding of the spread, prevention or treatment diseases, advance medical technology and treatment of traumatic injuries, or further basic science principles upon which other discoveries will be based, in ways that could otherwise not be achieved.
This recent article about how mouse adult stem cells are able to repair muscle damage in mice, is perfect example of necessary animal research. This research could not be conducted in silico (that is, on a computer), because researchers would only be hypothesizing how it might work and could never know for sure whether the adult stem cells did or did not regenerate the muscle tissue.
On a side note - how cool is it that the scientists were able to track these cells by making them glow under ultraviolet light! (I can just envision that the next wave of body modification may be to implant fluorescent cells into ones body.)
I admit, my personality is such that I would find it immensely difficult to injure the mice, and eventually, sacrifice them. But my personal feelings do not cloud my judgement that this type of research is necessary to help people with debilitating muscle trauma.