PainScience.com Sensible advice for aches, pains & injuries
 
 

Only the salamander can regenerate entire complex joints & limbs. How do they do it? No one knows!
Painting by illustrator Gary Lyons.

Salamander and Regeneration Science

Why does PainScience.com have a salamander mascot? Their regenerative superpower is an inspiring, profound example of what is possible in biology and healing

Salamanders are a biological marvel: they are the only larger vertebrates that can regenerate entire limbs, a capacity for healing unmatched in the animal kingdom. Lizards can grow new tails, and human children can regrow the tips of their fingers, but only the salamander can cook up perfect shoulders, elbows, wrists and hands from scratch.

And it’s a perfect mystery how they do it. If we only understood how their cells do this wonderful thing, what else would we know about biology and healing? How would it change health care? Our ignorance and our potential are dizzying.

And yet progress has been made. In 2010, researchers were able to trigger impressive regrowth of joint surfaces in rabbits.1 We’ve also found a mammalian gene that suppresses regenerative function. When the gene is turned off, presto: animals that couldn’t regenerate suddenly can!2

Forget jetpacks: I want the future to bring us regeneration powers!

The salamander’s talent is an ideal example of and symbol for healing, and for what health care professionals do — for how much there is to learn, and for learning itself, the regeneration of our minds if not our limbs!

Regeneration powers, anyone?

It’s pretty pie in the sky still, but the genetic potential actually exists to heal almost magically from massive injuries — just like the comic book character, Wolverine … & salamanders.

Wounds that do not heal

Most of the time it’s hard not to heal. You couldn’t stop it if you tried. The body is going to bounce back from most kinds of injuries, almost no matter what — it’s just a matter of time, with or without tricks like icing or soaking in an Epsom salts bath. It’s infamously impossible to rush healing.

Or is it?

But stubborn pain problems, the subject of this website, are different by definition. Or healing itself fails, or pain persists even when the tissues seem to be fine (like common muscle aches), or a bit of both. Repetitive strain injuries, which usually afflict connective tissues like the it band, plantar fascia, or the wrapping around your shin bones, are slow-motion traumas that often seem immune to recovery — this is what makes them both terrible and fascinating. They usually don’t heal because they need more rest than most people will give them, but sometimes healing just doesn’t work. Sometimes bone fractures and lesions will not close (a problem every surgeon dreads). Sometimes pain persists because of a known glitch in biology!

The regenerative healing powers of the salamander are amazing and bizarre… but they are also darkly reflected in the human wounds that do not heal. It doesn’t seem fair: salamanders can regenerate entire limbs, but we often can’t recover from a little overuse!

Other kinds of critter regeneration

The African spiny mouse

The only mammal with some impressive regenerative powers.

Many tiny organisms are masters of regeneration. But it’s rare in animals larger than a speck, and particularly rare in mammals. If regeneration is possible in any mammal, then there’s hope for us.

And it is possible. This neat 2012 science story is promising: “Biologist discovers mammal with salamander-like regenerative abilities.”3 The African spiny mouse does a far better job at regenerating any part of itself than any other known mammal to date. Salamanders are much better at regeneration, in every way, but at least we know mammals aren’t completely left out of the regeneration game.

And there are many other examples of limited critter regeneration of specific body tissues and parts.

The mole rat’s superpower

This isn’t about salamanders or regeneration, but I think I’m going to start turning this page into a general collection of cool biology of pain and healing throughout the animal kingdom.

“To deal with their miserable lives” naked mole rats evolved to feel no pain:

And yet in this harsh environment, under extremely crowded conditions, the naked mole rat has evolved to be virtually indestructible: these small mammals almost never get cancer, live to be over 30 (much longer than other rat species), and they are insensitive to acid burns. Now a new study in Cell Reports reveals one secret behind these rats’ abilities. Evolutionary tweaks to the amino acids in their pain receptors make naked mole rats extremely insensitive to pain after they are born.

I think it’s surprising and fascinating that immunity to pain isn’t a more common adaptation in biology. Clearly pain has potent survival benefits — the ultimate double-edged sword.

This salamander is skeptical

The PainScience.com salamander is more of a mascot than a logo. He’s a character. He has represented this website with a bit of flair since the very beginning (since before it was even called PainScience5).

The PainScience.com salamander does not believe everything he hears. The salamander is no sucker. The salamander watches MythBusters, and applies the same attitude here: let’s just check that. Sometimes the salamander squints at stupid ideas in health care and says, “Meh, not even even worth testing.”

When something seems too good to be true, the salamander rolls his beady little eyes, heaves a sigh, and gets ready to do brain battle with the forces of the evil Lord Gullible. The salamander is especially irritated by big promises. He is just not that impressed by a lot of expensive therapies and products, like acupuncture or Traumeel.

The salamander is living, breathing proof that there are miracles enough in biology without inventing new ones.

Sometimes you just need to hear sense from a salamander.

Fine, dash my hopes with all your crazy logic and science. Be that way.

funny reader

Related Reading

What does electricity have to do with salamanders? Read all about it! The body electric: electromagnetism and the foundation of life, a book by Robert O Becker and Gary Selden. amazon.com

Are you skeptical too? See the PainScience Reading Guide for Skeptics.

This guy was the model for the painted salamander logo at the top of the page.

What’s new in this article?

2016New section about the naked mole rat’s pain immunity superpower.

Notes

  1. Lee CH, Cook JL, Mendelson A, et al. Regeneration of the articular surface of the rabbit synovial joint by cell homing: a proof of concept study. Lancet. 2010 Aug;376(9739):440–8. PubMed #20692530. PainSci #54932.

    Build it and the cells will come. This proof-of-concept study demonstrated what happens if you replace the end of a rabbit’s femur with an empty plastic “scaffolding” of exactly the same shape, and then fertilize it with transforming growth factor beta3. Cells migrate into the framework and start building bone and cartilage! “The entire articular surface of the synovial joint can regenerate without cell transplantation.” Without the growth factor, not much happened: much less than half as many cells moved into the new habitat.

    These findings suggest that “regeneration of complex tissues is probable by homing of endogenous cells.”

    BACK TO TEXT
  2. PopSci.com [Internet]. Humans Could Regenerate Tissue Like Newts By Switching Off a Single Gene; 2010 Mar 16 [cited 15 Aug 5]. BACK TO TEXT
  3. Seifert AW, Kiama SG, Seifert MG, et al. Skin shedding and tissue regeneration in African spiny mice (Acomys). Nature. 2012 Sep;489(7417):561–5. PubMed #23018966. PainSci #54267. BACK TO TEXT
  4. Citation needed and harder to find than I hoped, but entomologist Gavin Pitts talks it up around the 5:00 mark in the Caustic Soda episode “Web Building Spiders.” BACK TO TEXT
  5. PainScience.com was “SaveYourself.ca” for more than a decade, but I never really liked it. I was always uneasy with the connotations of “save”: it smacked of a healing promise I can’t keep, and like Jesus might be involved somehow. I moved everything PainScience.com in late 2014. For more information, see Moving to PainScience.com: About the big move in 2014 from SaveYourself.ca to PainScience.com. BACK TO TEXT