A freshwater zebrafish’s spinal cord can heal completely after being severed - a paralyzing and often fatal injury for humans. While watching these fish repair their own spinal cord injuries, Duke University scientists have found a particular protein important for the process and their study could generate new leads into tissue repair and therapy for spinal injuries in humans. Of dozens of genes strongly activated by injury, seven coded for proteins that are secreted from cells. One of these - called CTGF or connective tissue growth factor - was intriguing because its levels rose in the supporting cells, or glia, that formed the bridge in the first two weeks following injury. This animation shows the multi-step process of spinal cord healing after an injury. Supporting glial cells (shown in red) are first to cross the gap between the severed ends of the cord. Neuronal cells (green) soon follow. Humans and zebrafish share most protein-coding genes, and CTGF is no exception. The human CTGF protein is nearly 90% similar in its amino acid building blocks to the zebrafish form. When the team added the human version of CTGF to the injury site in fish, it boosted regeneration and the fish swam better by two weeks after the injury.