Level D· Scientific groundwork from lab and animal studiesAnimal StudyEurope PMCOpen access

Creation of knockin mice for the fluorescence protein based in vivo identification of skeletal myofiber types

Mori S., Omura T., Kono M., Fukunaga T., Koseki H., Shigemoto K.

Animal Study, published in Sci Rep (2025) — summary generated from the PubMed abstract.

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Level D· Scientific groundwork from lab and animal studiesEvidence level of this study

Evidence from laboratory and animal studies provides groundwork for understanding mechanisms and potential before human studies continue.

  • Level A · Stronger Clinical Evidence
  • Level B · Emerging clinical evidence with positive signals
  • Level C · Early human research exploring benefits
  • Level D · Scientific groundwork from lab and animal studies
  • Emerging · Emerging topic under active research
Read the A–D evidence level guide

This page is generated from the PubMed record. The Thai description is an automated summary of bibliographic fields and the abstract, not a full translation, and is not medical advice.

Study type
Animal Study
Journal
Sci Rep (2025)
Reported sample size
—
Source database
Europe PMC
PMID
40181133
PMCID
PMC11968920
DOI
10.1038/s41598-025-96118-z

Abstract (original English)

Skeletal muscles of the mammalian trunk and limbs comprise myofibers that express four types of myosin heavy-chain (MyHC) isoforms, each with distinct contractile and metabolic properties. Despite histochemical and immunohistochemical staining to identify myofiber types, all myofiber types cannot be identified simultaneously in vivo. In this study, we generated a novel knock-in mouse model, termed "MusColor," that enables the simultaneous identification of individual MyHC isoforms through the expression of four fluorescent proteins. The identification of fibre types by fluorescent expression in MusColor mice was consistent with that achieved by immunostaining and had higher sensitivity. By studying the aging-associated changes in myofiber types using the MusColor mice, we were able to identify changes in hybrid myofibers that simultaneously express multiple MyHCs. Furthermore, by culturing satellite cells isolated from MusColor mice and treatment of thyroid hormone or rapamycin, changes in myofiber type and metabolic function could be analysed in living cells. The MusColor mouse proved useful for elucidating the mechanisms of muscle fibre changes caused by diseases such as sarcopenia, neuromuscular and metabolic diseases, as well as by exercise and nutritional environments.

What this study does not prove

  • • This study does not prove SVF is an approved treatment or a replacement for standard care.
  • • This is preclinical work; animal or laboratory results cannot be applied to humans.

Evidence level

Evidence from laboratory and animal studies provides groundwork for understanding mechanisms and potential before human studies continue.

How we grade evidence
Muscle, SkeletalSatellite Cells, Skeletal MuscleAnimalsMice, TransgenicMiceMyosin Heavy ChainsLuminescent ProteinsProtein IsoformsMuscle Fibers, SkeletalGene Knock-In Techniques

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