Controlled release of IGF-I from a biodegradable matrix improves functional recovery of skeletal muscle from ischemia/reperfusion

Authors

  • David W. Hammers,

    1. Department of Kinesiology, The University of Texas at Austin, Austin, Texas
    2. Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712; telephone: (512) 471-3604, fax: (512) 471-0616
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  • Apurva Sarathy,

    1. Department of Kinesiology, The University of Texas at Austin, Austin, Texas
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  • Chantal B. Pham,

    1. Department of Kinesiology, The University of Texas at Austin, Austin, Texas
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  • Charles T. Drinnan,

    1. Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712; telephone: (512) 471-3604, fax: (512) 471-0616
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  • Roger P. Farrar,

    1. Department of Kinesiology, The University of Texas at Austin, Austin, Texas
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  • Laura J. Suggs

    Corresponding author
    1. Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712; telephone: (512) 471-3604, fax: (512) 471-0616
    • Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712; telephone: (512) 471-3604, fax: (512) 471-0616.
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Abstract

Ischemia/reperfusion (I/R) injury is a considerable insult to skeletal muscle, often resulting in prolonged functional deficits. The purpose of the current study was to evaluate the controlled release of the pro-regenerative growth factor, insulin-like growth factor-I (IGF-I), from a biodegradable polyethylene glycol (PEG)ylated fibrin gel matrix and the subsequent recovery of skeletal muscle from I/R. To accomplish this, the hind limbs of male Sprague–Dawley rats were subjected to 2-h tourniquet-induced I/R then treated with saline, bolus IGF-I (bIGF), PEGylated fibrin gel (PEG-Fib), or IGF-I conjugated PEGylated fibrin gel (PEG-Fib-IGF). Functional and histological evaluations were performed following 14 days of reperfusion, and muscles from 4-day reperfusion animals were analyzed by Western blotting and histological assessments. There was no difference in functional recovery between saline, bIGF, or PEG-Fib groups. However, PEG-Fib-IGF treatment resulted in significant improvement of muscle function and structure, as observed histologically. Activation of the PI3K/Akt pathway was significantly elevated in PEG-Fib-IGF muscles, compared to PEG-Fib treatment, at 4 days of reperfusion, suggesting involvement of the pathway PI3K/Akt as a mediator of the improved function. Surprisingly, myoblast activity was not evident as a result of PEG-Fib-IGF treatment. Taken together, these data give evidence for a protective role for the delivered IGF. These results indicate that PEG-Fib-IGF is a viable therapeutic technique in the treatment of skeletal muscle I/R injury. Biotechnol. Bioeng. 2012; 109:1051–1059. © 2011 Wiley Periodicals, Inc.

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