Title

Macrophage Colony Stimulating Factor-Induced Macrophage Differentiation Influences Myotube Elongation

Document Type

Article

Publication Date

1-2013

Publication Title

Biological Research for Nursing

Volume

15

Issue

1

First page number:

62

Last page number:

70

Abstract

Background: Unaccustomed exercise, high-intensity dynamic sports activities, or the resumption of normal weight-bearing after a period of disuse can induce skeletal muscle injury, which activates an inflammatory response followed by muscle regeneration. Specific subsets of macrophages are involved in muscle regeneration. But the exact role of macrophage differentiation during muscle regeneration remains to be elucidated.

Objective: The objective of the study was to examine the effect of macrophage colony stimulating factor (M-CSF)-differentiated, lipopolysaccharides (LPS)-stimulated-macrophage-conditioned medium on muscle-cell proliferation, fusion, and elongation, which are key events during muscle regeneration and myogenesis.

Method: Murine C2C12 myoblasts were cultured in conditioned medium obtained from PU5-1R macrophages that were (a) undifferentiated, unstimulated; (b) M-CSF-differentiated, unstimulated; (c) undifferentiated, LPS-stimulated; or (d) M-CSF-differentiated, LPS-stimulated. Myoblast proliferation ratio, nuclei number, and length were measured.

Results: C2C12 cells cultured in conditioned medium from M-CSF-differentiated, LPS-stimulated macrophages had significantly more nuclei and greater length than cells cultured in conditioned medium from undifferentiated, LPS-stimulated macrophages. Dilution and denaturization of the M-CSF-differentiated, LPS-stimulated-macrophage medium prevented a marked increase in C2C12 nuclei number and length. However, the C2C12 myoblast proliferation ratio was significantly greater in conditioned medium from undifferentiated, LPS-stimulated macrophages than in conditioned medium from M-CSF-differentiated, LPS-stimulated macrophages.

Conclusions: M-CSF-differentiated, LPS-stimulated macrophages may influence myogenesis and the early and terminal stages of muscle regeneration. This knowledge may aid in developing therapies that will directly expedite muscle repair and lead to faster rehabilitation and reduced rehabilitation costs.

Keywords

C2C12 Myoblasts; Colony Stimulating Factor; Colony-stimulating factors (Physiology); Endotoxins; Exercise; Inflammation; Macrophages; Muscles—Regeneration; Muscles--Wounds and injuries; Myoblasts; Myogenesis; Myotube Fusion; PU5-1R Macrophages; Sports

Disciplines

Community Health | Kinesiology | Nursing | Physical Therapy | Rehabilitation and Therapy | Sports Sciences

Language

English

Permissions

Use Find in Your Library, contact the author, or interlibrary loan to garner a copy of the item. Publisher policy does not allow archiving the final published version. If a post-print (author's peer-reviewed manuscript) is allowed and available, or publisher policy changes, the item will be deposited.

Identifier

DOI: 10.1177/1099800411414871

UNLV article access

Search your library

Share

COinS