Amputated frog leg, successful experiment to regenerate perfectly in a year and a half : Donga Weekly

The results of an experiment in which a frog’s recently lost leg was completely regenerated after 18 months have been published in an academic journal. The subject of the test was the African clawed frog, a pet frog with a lifespan of around 20 years. After about 24 hours of wrapping the amputated leg with a gel-like medicine, about 18 months later, surprisingly, new bones, skin, nerves and blood vessels were created, and the leg, including the web and toes, completely regenerated. Although there have been similar studies in the past, it is difficult to see that the regenerated frog legs are exactly the same as the original legs in terms of form or function. Of course, some frogs grow new limbs when limbs are amputated. However, it is meaningful because it is a case that shows that regeneration is possible through medical treatment by selecting an adult species that does not spontaneously regenerate limbs.

To regenerate the amputated leg, the researchers prepared a silicone membrane called a BioDome, which was filled with a medicated silk protein and carefully wrapped around the amputated leg away. In fact, the arms and legs are structurally very complex, so they are not easily regenerated. As a result, it is usually easy to go in the direction of healing the wound rather than regenerating it back to its original shape. This is because the direction of stopping the bleeding and preventing infection is more favorable for survival than regeneration. Therefore, it is possible to prevent the healing effect of the wound as much as possible and use a drug that induces the development of blood vessels or muscles to establish an environment suitable for regeneration. In the end, it was confirmed that most of the frogs tested had regenerated legs in near-perfect form, including the tip of the toes. He successfully demonstrated that the type of drug used and its use was appropriate. Of course, applying the results obtained from frogs to mammals requires a completely different approach. However, the fact that an environment for regeneration has been artificially created and successfully repaired is a sign of a surprising miracle.

A self-healing plastic that heals on its own

Planaria. [GETTYIMAGES]

The desire for regenerative therapy was also in the engineers. Even a person can heal a minor skin wound without taking any other measures. However, a broken smartphone screen never returns to its original state no matter how long you wait, so you have to go to a service center to get it repaired. Wouldn’t it be great if he could be restored on his own as a human being in this situation? Therefore, self-healing plastic is the material that emerged. In 2014, the international academic journal ‘Science’ presented a self-healing plastic in a shape very similar to the shape of the human body. The interior of the plastic is full of microcapsules, and like human skin, when a wound occurs, the microcapsules burst and the released substances fill the cracks and fix them more firmly. . There is also a way to fill the cracks by flowing out of a wound when a healing substance flows through a small tube like a blood vessel. As a result of the actual experiment, the hole with a diameter of about 1 cm was restored to its original state in 20 minutes. It seems that it would be good to use it on the surface of equipment that is difficult to repair because it is out of reach of human hands.

Other animals that regenerate their own bodies

There are animals that can regenerate around us. There is a story that if you cut a worm in half, it will regenerate in two. However, in reality, as large organs such as the brain and heart are only in the front part of earthworms, the severed front part can regenerate the tail, but the remaining back part cannot regenerate the head. Maybe that’s why the rumors came about because the broken part keeps moving until it runs out of power. Conversely, when a fingernail-sized flat animal is cut, the head regenerates the tail and the tail regenerates the head, resulting in two complete animals. The same goes for disassembling into thirds, and it is said that the entire body can be regenerated with only the remaining parts even if it is dismembered. Being able to recreate a head everywhere in an animal with a separate head means that every cell remembers the whole body, which is a really great thing.

starfish [GETTYIMAGES]

In Japanese fishing villages in the 1950s, starfish often became entangled in nets, disrupting fishing. Fishermen started dumping the stinging starfish in pieces into the sea, but surprisingly, all the pieces were regenerated and multiplied in number, and the population increased rapidly after that. In the case of a similar sea cucumber, it regenerates unconditionally even if any part is cut, and even if all the intestines are removed, the intestines are regenerated in the same place. As a result, there is a type of sea cucumber that survives in a form of disturbance by spilling its guts in an emergency where predators can eat it.

right par [GETTYIMAGES]

There is a cute looking salamander called Uparupa that lives in central Mexico. Among the fictional characters in the ‘Pokémon’ cartoon, ‘Right’ came with an open mouth with a blank expression from here. Its official name is Axolotl, but its legs and tail regenerate naturally, and even if part of its brain is damaged, it returns to its original state. Where is Righta Loopa’s ability to regenerate almost every part of the body if he is injured to the point of not dying? The research team deciphered the genome of the leaf and found that it has 32 billion pairs of base sequences, which is almost ten times the length of humans. Of course, not all of them are excellent, but the secret of their excellent regenerative ability was hidden throughout the long nucleotide sequence. Once damaged somewhere, certain growth-related genes among the right parrot’s genes continue to work hard for several months. Then, cells in the damaged area divide to create a new body. When wounded, these genes only function for a very short period of time in humans, but individuals like the right parupa are expressed for a long time and acquire excellent regenerative capacity. Additionally, it is assumed to have less differentiated cells. It is said that they have cells which are like emergency supplies which are not yet used and they use them appropriately in case of an unexpected accident.

It is not easy to regenerate when the outside of the body is injured or damaged, but sometimes internal organs are regenerated. In the case of the liver, which is a large and complex organ in our body, it heals in about 6 months even if it is removed by surgery. Lungs regenerate surface cells every 3 weeks. It is known that the heart does not regenerate well, but there is a story that it restores its condition on its own several times in a lifetime. Jangdo is regularly attacked by stomach acid, so he sustains himself while regenerating. The eye, of course, cannot regenerate, but surprisingly, in the case of the cornea, when it is damaged, it heals within a day.

A life of disease-free longevity dreamed of through regenerative medicine

Our organs can eventually regenerate over time. Then, what is the reason that the outside of the body is not regenerated? As mentioned earlier, if the process to stop bleeding and prevent infection is beneficial for survival and instead hinders regeneration, wouldn’t this natural process be at a disadvantage? In some circumstances, the loss of certain body parts can be detrimental to survival. Even if it takes time, returning to the original state is sometimes useful in later survival. If you think about it, you can see that most of the animals with excellent regenerative abilities live in water. The same is true of human organs, which are always in liquid. As a result, it is impossible to say for sure why it regenerates under these circumstances, but it can be confirmed that establishing a similar environment helps the body to regenerate. The outside of the body can also be regenerated by creating an environment inside the amniotic fluid. In science fiction films, when recovering a body or describing a situation where a person is resurrected from the dead, scenes are usually shown floating naked in a huge tank. Clones also exist mostly in transparent cylinders filled with liquid. Focusing on a similar approach, the research team regenerated frog legs with perfect functions by carefully covering the damaged area and its surroundings with a substance called Biodome in the form of a protein gel mixed with drugs. This was the first button for regenerating the body.

As regenerative medicine advances, the era of making and transplanting custom organs may come. [GETTYIMAGES]

More than 185,000 amputations or deletions are performed each year in the United States alone. It is estimated that by 2050 there will be 3.6 million people without arms or legs. Although this study can be a major indicator for such external recovery, the field of organ transplantation is also receiving new expectations. As Korea moves into an aging society, the demand for organ transplants is on the rise. However, there is a worldwide shortage of donor organs, so many people die while anxiously waiting for an organ transplant. In this situation, if organs or tissues can be regenerated from the outside as separate parts, a perfect heart without immune problems can be created using the patient’s cells and replaced with a broken heart. It means you can create and transplant organs that are tailored for you, rather than accepting other people’s organs as they currently are.

Longevity without disease is difficult because once you get sick, longevity is also difficult. In particular, it is difficult to see it as a treatment that helps our body actively repair itself, as many treatments aim to prevent the development of the disease. However, since regenerative medicine is a major task of regenerating damaged tissues, it can introduce a new aspect in the word treatment. If enough research is done and organs can be made at a level that can be applied to humans, there may be a world in the future where people live long lives by constantly replacing disposable organs regardless of whether they get sick or not.

In fact, an indefinite recovery with no restrictions is like unearned income without working. There are many opportunity costs to recovery under any circumstance, so we are forced to spend a lot of rest and leisure time to seek the most complete individual recovery. That’s why sometimes you need a planned recharge time. Even if science and technology develop infinitely one day and have the ability to recover from fatigue indefinitely, it may be difficult to eliminate recreational activities that give us happiness just by imagining, regardless be it their health or longevity. I hope that the joy and recovery of the mind, as well as the regeneration and recovery of the body, will harmonize, leading to a truly happy and disease-free longevity.

_{The track is…
After graduating from Yonsei University’s Department of Astronomy and Space, he worked at the Space Monitoring Center of the Korea Institute of Astronomy and Space Science and Yonsei University’s Space Flight Control Laboratory. Under the stage name of ‘orbit’, he runs the podcast ‘Changchang’, ‘Unfortunate Science’ YouTube and ‘Too Much Science’, and his book is ‘The Science of Orbit’.}

Donga Weekly No. 1363 (p58~60)