A strain of mice that have the natural ability to repair damaged cartilage has been discovered by researchers at Oregon Health and Science University.
They believe that the mice strain they dubbed MRL/MpJ may one day prove helpful in improving treatments for human knee, shoulder, and hip injuries.
"We think there is something special about these mice. They have the ability to regenerate cartilage," said Dr. Jamie Fitzgerald, assistant professor of orthopedics and rehabilitation in the OHSU School of Medicine.
"Knee pain is one of the most common musculoskeletal complaints that bring people to their doctor.
"Human cartilage injuries heal poorly and can lead to cartilage degeneration and osteoarthritis. This is an enormous clinical problem. It is estimated that one quarter of the adult population will have some kind of arthritis by 2020," Fitzgerald added.
The researcher revealed that the study was started with the initial grant coming from the National Football League Charities, as knee injuries are a significant issue for professional athletes.
"Cartilage injuries can be career-ending for football players," Fitzgerald said.
During the study, Fitzgerald and his colleagues Dr. Andrea Herzka and Cathleen Rich studied knee injuries in 150 mice.
The results of the study that were recently published in Osteoarthritis and Cartilage suggest that three months after the cartilage in their knees was damaged, male MRL mice had replaced a significant amount of the injured tissue with healthy cartilage.
Chris Little, director of the Raymond Purves Bone and Joint Research Laboratories in Sydney, Australia, and one of the scientists involved in the project, says that the finding is significant for human health.
"The research we have published is an early, but important step in unravelling the important pathways that will facilitate development of new treatments," says the researcher.
The researchers have revealed that their next step will be to try to understand why these mice are able to restore the cartilage in their knees.
"If we can identify what genes or proteins are necessary for cartilage to heal, we can work toward finding similar genes and proteins in humans," Herzka says.
An actual treatment, however, "is many years away", say the researchers.