Icing after skeletal muscle injury with necrosis in a small fraction of myofibers limits inducible nitric oxide synthase-expressing macrophage invasion and facilitates muscle regeneration.
Am J Physiol Regul Integr Comp Physiol
; 324(4): R574-R588, 2023 04 01.
Article
em En
| MEDLINE
| ID: mdl-36878487
Growing evidence from animal experiments suggests that icing after skeletal muscle injury is harmful to muscle regeneration. However, these previous experimental models yielded massive necrotic myofibers, whereas muscle injury with necrosis in a small myofiber fraction (<10%) frequently occurs in human sports activities. Although macrophages play a proreparative role during muscle regeneration, they exert a cytotoxic effect on muscle cells through an inducible nitric oxide synthase (iNOS)-mediated mechanism. In this study, we established an animal injury model with necrosis limited to a small myofiber fraction and investigated the effect of icing on muscle regeneration with a focus on macrophage-related events. Icing after muscle injury of this model resulted in an enlarged size of regenerating myofibers compared with those in untreated animals. During the regenerative process, icing attenuated the accumulation of iNOS-expressing macrophages, suppressed iNOS expression in the whole damaged muscle, and limited the expansion of the injured myofiber area. In addition, icing increased the ratio of M2 macrophages within the injured site at an earlier time point than that in untreated animals. Following these phenomena in icing-treated muscle regeneration, an early accumulation of activated satellite cells within the damaged/regenerating area occurred. The expression level of myogenic regulatory factors, such as MyoD and myogenin, was not affected by icing. Taken together, our results suggest that icing after muscle injury with necrosis limited to a small fraction of myofibers facilitates muscle regeneration by attenuating iNOS-expressing macrophage invasion, limiting muscle damage expansion, and accelerating the accumulation of myogenic cells which form regenerating myofibers.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Células Satélites de Músculo Esquelético
/
Doenças Musculares
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Am J Physiol Regul Integr Comp Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
Japão