Associate Professor Mitsunori Miyazaki, Graduate School of Biomedical Sciences, Hiroshima University; Associate Professor Rinto Shimotsuru, Graduate School of Veterinary Medicine, Hokkaido University; Associate Professor Yu Kitaoka, Faculty of Human Sciences, Kanagawa University; Takahashi, Graduate School of Arts and Sciences, University of Tokyo A research group led by Assistant Professor Kenya found that the skeletal muscles of Asian black bears do not weaken during hibernation, even though they are inactive by entering an energy-saving mode.
According to Hiroshima University, skeletal muscles, which are the muscles that move the body, grow in size the more they are used, but weaken when inactive.However, hibernating animals such as bears maintain various bodily functions even for long periods of inactivity.The mechanism has not been elucidated so far.
The research group collected muscles from eight hibernating Asian black bears and compared them with the muscles of the same individual during the active period.As a result, it was confirmed that there was no change in the fiber size of skeletal muscle and the ratio of slow-twitch and fast-twitch fibers, and that there was no decline at all.
On the other hand, the functions that control intracellular information transmission and promote the breakdown of muscle proteins were suppressed.Furthermore, it was found that the function of regulating lipid metabolism was remarkably suppressed.The research group believes that black bears prevent their skeletal muscles from weakening during hibernation by putting their bodies into energy-saving mode.
However, it has not been clarified yet what the switch to enter this energy saving mode is.The research group believes that elucidating this point will help develop effective rehabilitation methods for humans and prevent bedridden patients.
Paper information:[Scientific Reports] Regulation of protein and oxidative energy metabolism are down-regulated in the skeletal muscles of Asian black bears during hibernation