Unlike reptiles, humans cannot regenerate limbs, but we can regenerate and repair large portions of our ribs. Employing CT imaging, the healing of the human limb was monitored after a human rib was partially removed surgically. Eight centimeters of a rib and one centimeter of a cartilage was removed. These portions partially regenerated and repaired in six months. At the same time, three to five millimeters of rib cartilage was surgically removed from mice, to better understand the regeneration process.
The researchers from the University of Southern California, Los Angeles, California, found that when they removed both rib cartilage and its surrounding sheath of tissue – called the “perichondrium,” the missing sections failed to repair even after nine months. However, when they removed rib cartilage but left its perichondrium, the missing sections entirely repaired within one to two months.
Also, they found that a perichondrium retains the ability to produce cartilage even when disconnected from the rib and displaced into nearby muscle tissue – further suggesting that the perichondrium contains stem cells. This is good news for all researchers working on stem cells.
Full details of the discovery can be accessed here.