Cartilage That Repairs Itself

Greg Oden, NBA player with the Portland Trail Blazers, missed his rookie season because of a cartilage injury. And although it wasn’t his main injury, champion golfer Tiger Woods has been sidelined after surgery on damaged cartilage in his left knee. Now, mice with natural ability to regenerate cartilage may help scientists improve treatment of human injuries.

OHSU researchers have discovered that male mice from a strain called MRL/MpJ can naturally repair their own knee cartilage. “Knee pain is one of the most common musculoskeletal complaints that brings people to the doctor,” said Jamie Fitzgerald, Ph.D., assistant professor of orthopedics and rehabilitation in the OHSU School of Medicine. . “Human cartilage injuries heal poorly and can lead to cartilage degeneration and osteoarthritis. It is estimated that one quarter of adults will have some kind of arthritis by 2020.”

Knee injuries are also crucial for professional athletes. The National Football League Charities provided the initial grant to launch the study. “Cartilage injuries can be career-ending for football players,” Fitzgerald said.

Fitzgerald and OHSU physician Andrea Herzka, M.D., and researcher Cathleen Rich studied knee injuries in 150 mice. Three months after cartilage in their knees was damaged, male MRL mice had replaced much of the injured tissue with healthy cartilage. The study results appeared in the medical journal Osteoarthritis and Cartilage.

The next step is understanding why these mice are able to restore the cartilage in their knees. Though a treatment based on these findings is years away, the research is an important first step.  “If we can identify what genes or proteins are necessary for cartilage to heal, we can look for similar genes and proteins in humans,” Herzka says.