By identifying this "factor" in bear serum during hibernation, it is possible to develop effective rehabilitation strategies in humans and prevent them from becoming bedridden in the future.
In hibernation, bears can lie down for 5-7 months a year in their dens without eating or drinking, but if humans try to lie still for only 3 weeks, they will lose muscle mass, and if the period is prolonged for more than that, this may lead to related diseases sedentary lifestyles such as obesity, diabetes and even early death.
However, bears end their hibernation with limited muscle loss, minimal metabolic dysfunction, and healthy bodily function, which scientists have been trying for years to figure out how it occurs, and a new study published in the journal PLOS One indicates that the solutes In bear's blood are the answer, which can help prevent human muscle atrophy.
A report published on the Science Alert website states that researchers from Hiroshima University in Japan, in collaboration with researchers from Hokkaido University, used serum from Japanese black bears during hibernation to weaken the "destruction mechanism" that It causes myasthenia gravis.
The researchers took the serum from the blood of 7 hibernating bears and added it directly to tissue cultures of human skeletal muscle cells. Muscle mass is generally determined by the dynamic equilibrium between “synthesis” and “degradation” of proteins. During hibernation , the researchers observed an increase in the protein content of cells within 24 hours, and at the same time there was a decrease in the production of a regulatory protein that plays an important role in getting rid of unused muscle.
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However, these cellular changes only appeared when blood from hibernating bears was added. When blood was taken from active black bears in summer, the serum did not stop the natural process of protein degradation in human skeletal muscle cells.
"Some factors present in bear serum during hibernation may regulate protein metabolism in cultured human skeletal muscle cells and contribute to the maintenance of muscle mass," says physiologist Mitsunori Miyazaki of Hiroshima University in the press release posted on the university's website on July 15. However, the identification of this "factor" has not yet been achieved.
The researchers attribute the impairment of the muscle's "destruction machinery" to the muscle protein-1 (MuRF1), which is the key to muscle wasting unused, and they also observed increased levels of the growth hormone "insulin-like growth factor-1" (IGF-1) in the serum of the bear. during hibernation.
But Miyazaki and colleagues recalculated the serum GH concentration levels of the bear during hibernation, and said that it is possible that the higher GH concentrations observed in the study were simply due to lower serum water content due to other causes, such as dehydration.
Not the first attempt to understand
Similar studies have been done on black bear serum in the past, but none have succeeded in identifying the "factor" that causes this, and in 2018 the serum of bears during hibernation produced a decrease in the rate of protein change in human skeletal muscle tissue, and a similar effect was shown in tissues of the black bear. muscle in mice.
Although this factor has not yet been identified, Miyazaki is determined to continue the search for answers, and he hopes that "by identifying this (factor) in the serum of a bear during hibernation and elucidating the undiscovered mechanism behind muscles that do not weaken even without their use" in hibernating animals, It is possible to develop effective rehabilitation strategies in humans and prevent them from becoming bedridden in the future.
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