In humans, muscles can only regenerate from small injuries, such as those resulting from sporting activities. After an accident or combat injury, large wounds often cause deep damage to muscles, which fail to regenerate and scar. Some animals, on the other hand, replace injured body parts perfectly. In a recently published study, researchers at the University of Fribourg describe how zebrafish regenerate several muscles after a deep wound at the base of their tail.
Muscle cells are similar in all vertebrates. Despite these similarities, fish and humans differ in their regenerative capacities. Zebrafish, which serve as model organisms in biology, can regenerate various organs, such as the heart, retina and limbs, which are not repaired in our bodies. But are these masters of regeneration also capable of replacing entire muscles? This question was investigated in the laboratory of biologist Anna Ja’wi’ska.
Complete regeneration in four weeks
To investigate the extraordinary regenerative capacity of zebrafish, a new method has been developed in which one side of the base of the tail is frozen for a few seconds. Such a deep wound damages a series of muscles and leads to a large wound. Scientists at the University of Freiburg have shown how stem cells are recruited to generate new muscle cells. Analysis of genetically modified zebrafish has shown that all varieties of muscle fibers are fully replaced four weeks after injury. The only difference is a reduced precision of muscle fiber arrangement. At the molecular level, the team discovered the signal required to activate regeneration, the TOR (target of rapamycin) signal. Deciphering the basis of natural regeneration in model organisms holds promising potential for biology and medicine: it provides insight into how large muscle injuries might be regenerated by new cells.
Publication: NPJ Regenerative Medicine 2024 Feb 20;9(1):8. doi: 10.1038/s41536’024 -00351-5, Skeletal muscle regeneration after extensive cryoinjury of caudal myomeres in adult zebrafish, Hendrik Oudhoff, Vincent Hisler, Florian Baumgartner, Lana Rees, Dogan Grepper, Anna Ja’wi’ska
