Lizard Tale: For the First Time in Millions of Years, Lizard Regrows ‘Perfect Tail'

What's really amazing about the research is what it can mean for humans healing wounds.

USC/Lozito Lab

It's not really news that lizards can regrow tails -- but what is big news is for the first time in 250 million years, a lizard regrew a "perfect" tail with the help of stem cells, and USC researchers said it can help decode human wound healing.

“Lizards have been around for more than 250 million years, and in all that time no lizard has ever regrown a tail with dorsoventral patterning, until now,” said Thomas Lozito, an assistant professor of orthopaedic surgery and stem cell biology and regenerative medicine at the Keck School of Medicine of USC. “My lab has created the first regenerated lizard tails with patterned skeletons.”

The study just released Wednesday found that for the first time in a long time, a lizard regrew a tail with skeletal and nerve tissue with the help of neural stem cells, the stem cells that build the nervous system.

What normally happens is lizards will regrow an "imperfect cartilage tube" -- not an actual tail with a spinal column a nerves, like the original tail.

USC/Lozito Lab
A fully regenerated mourning gecko tail. Muscle is colored in white, cartilage in red, proliferating cells in green, and cell nuclei in blue.

"This is one of the only cases where the regeneration of an appendage has been significantly improved through stem cell-based therapy in any reptile, bird or mammal, and it informs efforts to improve wound healing in humans," Lozito said.

Because even the NSCs typically can't regrow more than a "cartilage tube," the research team used gene editing. Then, they implanted the cells into the lizard's tail stump.

USC/Lozito Lab
A lizard species known as a mourning gecko can regenerate its tail, but the replacement is an imperfect copy of the original. Stem cells fix that.

What resulted was amazing, and groundbreaking.

"This study has provided us with essential practice on how to improve an organism’s regenerative potential," Lozito said. “Perfecting the imperfect regenerated lizard tail provides us with a blueprint for improving healing in wounds that don’t naturally regenerate, such as severed human limbs and spinal cords. In this way, we hope our lizard research will lead to medical breakthroughs for treating hard-to-heal injuries."

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