Researchers at Texas A&M University and Tulane University have found that treating amputation wounds in mice with two proteins encouraged growth of the residual bone and joint. Because the human skeletal structure is similar to a mouse, the researchers are optimistic that one day the discovery will help people with amputations regrow limbs.

The research team studying methods to stimulate tissue regeneration after traumatic injury previously discovered that treating toe amputation wounds in neonatal mice with a protein called BMP2 stimulated endochondral ossification to regenerate the residual bone. The team’s latest research, published February 5 in Nature Communications,found that also treating the amputation wound with a BMP9 protein stimulated regeneration of a synovial joint that forms an articulation with the residual bone.

Three days after applying the proteins to the wounds, the researchers found that over 60 percent of the residual bones had formed a layer of cartilage, as seen in joints, at the end of the bones. The result was more effective when the team treated the wounds first with BMP2 and then BMP9 a week later. Not only did the bones regrow, they also formed more complete joint structures with part of the new bones attached to them.

“Our study is transformational,” said Ken Muneoka, PhD, one of the study authors. He suggested that the experiment demonstrates that even though mammals can’t regenerate body parts, their cells know how to do it. “They can do it, they just don’t do it. So, we have to figure out what’s constraining them,” he told NewScientist.