MRL mice, as you might recall, are a laboratory breed that demonstrates extraordinary powers of regeneration for a mammal. Here, EurekAlert! notes large differences in their inflammatory response as well: " A strain of laboratory mice that has 'superhealing' powers has been found to resist inflammation after a knee injury, and also to avoid developing arthritis at the injury site in the long term ... Their findings illuminate the mechanisms of post-traumatic arthritis and could point to therapies for this condition ... The superhealer can almost regenerate tissue. We thought, 'if they can regenerate cartilage in the ear, what about cartilage in the knee?' This happened in our pilot study, and we now have taken these results further and learned what happens in terms of inflammation. If you can figure out why the animal is a superhealer and apply that to people, then you may help prevent the development of arthritis ... control mice showed a greater than 700-fold increase in the expression of one cytokine, [interleukin], in the first four hours after a fracture and 37-fold difference in that cytokine level at 7 days after the fracture. ... Interleukin generally promotes inflammation and an increase in temperature. The superhealer mice showed a similar trend, but in much lower amounts: a 70-fold peak in expression at day 0 down to a 3.5-fold increase by day 7."