This nearly amazing type of tissue development motivated scientists at Northwestern Polytechnical University in Xian, China, to investigate whether deer antlers could be of any use as a model for organ regeneration in mammals. The twist is that they set out to do so with a rather unorthodox experiment: by implanting deer stem cells into the foreheads of mice, which subsequently grew mini antlers.
Every spring, male deer begin sprouting bizarre, twisting structures out of their foreheads. The bucks head produces tissue at an excessive rate, causing the antlers to grow as quick as three-quarters of an inch each day. As the antlers grow, they branch into increasingly big forks. Every autumn, as soon as the mating season is over, the antlers fall off and the cycle starts once again. Thats in plain contrast to other animals with bony growths on their heads, such as rhinos, rams, and impala, whose horns grow when theyre young and stay for their whole lives.
Credit: Pixabay.
The pointy story of how antlers grow
New antler development starts at the pedicle, the growing base attached to the skull, and is regulated by hormonal agents like testosterone. The growth cycle coincides with the reproducing season, so males have solidified antlers that they can use to eliminate with other males to establish dominance and win breeding advantages.
In order to grow their valued antlers, bucks have to siphon nutrients from other parts of the skeleton, successfully activating reversible osteoporosis in other bones during the extreme breeding season. The toll of antler development is on par with pregnancy, which speaks volumes about the challenging nature of growing bones out of their foreheads.
Stages of antler growth.A) one day after antler shed, B) 15 days after shed, scab still connected, C) 30 days after shed, scab is shed (A, B, C very same animal), D) about 3 months after shed by various animal, E) about five months after shed antler development is finished, with one extra month used to finish solidifying and drying of velour (D and E exact same animal), andF) solidified antler with shreds of dried velour on a third animal. Credit: A-E, Steve Demarais, F, Dave Hewitt/ Mississippi State University Deer Ecology and Management Lab.
During the early development cycle, the antlers begin off as bumps, covered in a soft, velvet-like product which contains blood vessels and nerves. This velvet helps to supply the growing antlers with nutrients and oxygen, along with safeguard them as they develop. As the antlers reach their full size, the velour dries up and falls off in a process understood as velour shedding. At this stage, the blood ceases to flow to the antlers, which are now completely mineralized bones. After the reproducing season, cells begin to demineralize the bone in between the pedicle and antler, causing the antlers connection with the skull to damage and the antler to fall off.
This whole procedure is genuinely exceptional. Its akin to growing an entire femur bone in less than six months. All of this comes at an expense.
From growing antlers to growing lost limbs
It is maybe not unexpected that lots of scientists have looked at antlers and questioned if there are any lessons they could discover that might apply to medication and tissue regrowth. Wolfgang Pita Thomas, a neuroscientist at Washington University in St Louis, for example, is fascinated by the reality that nerves inside antlers restore ten times faster than nerves in people. She is presently actively researching methods to transform this fast growth into new treatments for our own worried systems that speed up the regrowth of broken nerves, such as in the case of a paraplegic injury.
Within 45 days of implantation of an unique subtype of stem cells, referred to as “antler blastema progenitor cells”, the mice grew relatively big bumps on their heads that look like early antler-like structures, total with cartilage and bone. Stem cells collected from shed antlers no greater than 5 days older produced the very best outcomes.
The findings appeared in the journal Nature.
Despite their over-the-top appearance, the implanted mice are healthy and the scientists intend to use their findings in scientific bone repair work and even limb regeneration. Certainly, theres still a long method to precede scientists can bridge the space from growing antlers on mice to regrowing an individuals missing limb, however you have to begin with somewhere.
This brings us to the Xia scientists, who initially zoomed in on the cellular makeup and gene expression characteristics of antler tissue throughout numerous stages of growth. Once they homed in on the stem cell populations most associated with antler growth, which were found in the antler pedicle, they separated them and then did something rather extreme: they placed those cells straight into the skulls of lab mice.
Antler stumps from the 2020 study.
This is not the very first time that scientists have attempted to grow antlers on mice. In 2020, another group, also from China, handled to grow antler stumps on the skulls of mice after implanting deer antler tissue right under the forehead skin.
The bucks head churns out tissue at an excessive rate, causing the antlers to grow as quick as three-quarters of an inch per day. As the antlers grow, they branch into increasingly big forks. Throughout the early development cycle, the antlers start off as bumps, covered in a soft, velvet-like material that contains blood vessels and nerves. As the antlers reach their full size, the velvet dries up and falls off in a process understood as velour shedding. After the reproducing season, cells begin to demineralize the bone between the pedicle and antler, causing the antlers connection with the skull to weaken and the antler to fall off.
