Leukocyte IGF-1 Receptor Expression during Muscle Recovery

    Authors

    M. S. Fragala; A. R. Jajtner; J. R. Townsend; A. M. Gonzalez; A. J. Wells; L. P. Oliveira; J. R. Hoffman; J. R. Stout;D. H. Fukuda

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    Abbreviated Journal Title

    Med. Sci. Sports Exerc.

    Keywords

    MUSCLE REPAIR; IMMUNE FUNCTION; COLD WATER IMMERSION; CRYOTHERAPY; RESISTANCE EXERCISE; INFLAMMATION; GROWTH-FACTOR-I; HEAVY-RESISTANCE EXERCISE; SKELETAL-MUSCLE; INJURY; MACROPHAGES; MONOCYTES; REGENERATION; LYMPHOCYTE; NEUTROPHIL; RESPONSES; Sport Sciences

    Abstract

    Introduction The insulin-like growth factor 1 (IGF-1) system plays a central role in anabolic cellular processes. Recently, a regulatory role of IGF-1 in the immune response for muscle repair has been suggested, but how it modulates the inflammatory process is largely unknown. We evaluated changes in leukocyte expression of IGF-1 receptors (IGF-1R) during recovery from resistance exercise to determine whether changes in the potential for IGF-1 interactions with leukocytes may mediate the role of IGF-1 in muscle repair. Methods Twenty resistance-trained men (18-35 yr) performed resistance exercise followed by cold water immersion (CWI) or control treatment (CON) on three consecutive days. Blood was sampled at baseline (PRE), immediately (IP), 30 min (30P), 24 h (24H), and 48 h after (48H) exercise. Circulating IGF-1 was assayed, and IGF-1 receptor expression (CD221) on gated circulating leukocytes (monocytes, granulocytes, and lymphocytes) was measured by flow cytometry. Time and treatment effects were analyzed with ANCOVA. Results Circulating IGF-1 significantly increased from PRE to IP as a result of resistance exercise, but no differences between CON and CWI were observed. Mean fluorescence intensity of CD221 on monocytes and granulocytes and percent of CD221+ granulocytes significantly increased at 30P (P < 0.000) and returned to preexercise levels by 24H. No treatment effects on monocytes or granulocytes were observed. On lymphocytes, mean fluorescence intensity of CD221+ significantly increased from PRE to 30P in CWI. Conclusions Changes in IGF-1 and its receptor on monocytes and granulocytes seem to be part of the mechanism that facilitates recovery from resistance exercise during earlier stages of muscle recovery. In addition, CWI seems to alter IGF-mediated responses on slower-acting lymphocytes, suggesting that its effects may be seen in later stages of muscle repair.

    Journal Title

    Medicine and Science in Sports and Exercise

    Volume

    47

    Issue/Number

    1

    Publication Date

    1-1-2015

    Document Type

    Article

    Language

    English

    First Page

    92

    Last Page

    99

    WOS Identifier

    WOS:000346354800013

    ISSN

    0195-9131

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