Good News Notes:
“The brain is the organ that orchestrates all the diverse functions and complex decisions that take place in biological systems. Despite its critical nature, it is equally as fragile: the neurons that make up the brain do not regenerate like many other cell types.
While cells found in many other organs constantly divide to replenish themselves or heal in case of injury, neurons do not divide and therefore cannot regenerate upon death. Injuries involving cell death in the brain are severe and often long-lasting—think concussions, strokes and head trauma.
It is of vital importance to protect the brain from damage and stresses than can lead to cell death. To uncover mechanisms by which we can protect these crucial cells, we look to nature. Amazingly, many organisms have evolved to live through periods of harsh conditions such as low oxygen, dehydration and freezing temperatures: these conditions would be lethal to a human brain, and yet these animals show no damage to their own.
Switching off
Generally, for animals to survive these periods of stress, they must induce a state of hypometabolism. Hypometabolism, or hypometabolic states, occurs when organisms shut down certain biological processes which are not immediately necessary for survival.
Some examples of animals which use hypometabolism include ground squirrels and bears, which hibernate, frogs, which freeze solid over the winter, and snails and certain frogs, which estivate (enter a state of dormancy) to survive periods of drought.
So, what exactly are the details of hypometabolism, and how does the brain use it to survive? Hypometabolism is a network of various molecular parts and processes that need to work together to achieve a global result: think of an orchestra symphony where the different instruments, notes and sections contribute to a whole.
MicroRNAs are short, single-stranded RNA molecules that target and attach to messenger RNA (the instructions for making a functional protein) to destroy them and prevent the protein from being made. This allows the protein to be switched off without actually changing the gene that codes for the protein to begin with. This allows microRNAs to change the expression of many different genes which could help brains survive.
By looking at the levels and types of microRNA found in the brain tissue of a variety of animals, our research has been trying to shed light on how these molecules make changes to gene expression and promote the survival of neurons through extreme conditions.
Preventing damage
One of the animals we study is the wood frog, Rana sylvatica, which can survive being completely frozen for extended periods without incurring any brain damage.
When tissues go through freeze-thaw cycles, they have to deal with ischemia: reduced or halted blood flow to a tissue. In humans, this commonly occurs alongside strokes and causes severe damage, often resulting in the death of large groups of cells. To prevent damage during ischemia, cells have to undergo vast metabolic changes….”
View the whole story here: https://phys.org/news/2022-04-naked-mole-rats-frogs-animals.html