Abstract
The Achilles tendon, while the strongest and largest tendon in the body, is frequently injured. Even after surgical repair, patients risk re-rupture and long-term deficits in function. Poly-N-acetyl glucosamine (sNAG) polymer has been shown to increase the rate of healing of venous leg ulcers, and use of this material improved tendon-to-bone healing in a rat model of rotator cuff injury. Therefore, the purpose of this study was to investigate the healing properties of liquid sNAG polymer suspension in a rat partial Achilles tear model. We hypothesized that repeated sNAG injections throughout healing would improve Achilles tendon healing as measured by improved mechanical properties and cellular morphology compared to controls. Results demonstrate that sNAG has a positive effect on rat Achilles tendon healing at three weeks after a full thickness, partial width injury. sNAG treatment led to increased quasistatic tendon stiffness, and increased tangent and secant stiffness throughout fatigue cycling protocols. Increased dynamic modulus also suggests improved viscoelastic properties with sNAG treatment. No differences were identified in histological properties. Importantly, use of this material did not have any negative effects on any measured parameter. These results support further study of this material as a minimally invasive treatment modality for tendon healing.
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Acknowledgments
This study was funded by Marine Polymer Technologies, Inc. and NIH/NIAMS supported Penn Center for Musculoskeletal Disorders Grant (5P30AR069619). We thank Stephanie Weiss for assistance with surgical procedures, and Peter Chan for assistance with histology.
Author Contributions
CAN and JH contributed to research design, data acquisition, analysis, interpretation, and drafting and editing the manuscript. SF contributed to research design and critical review of the manuscript. LJS contributed to research design, interpretation, and critical review of the manuscript. All authors have read and approved the final manuscript for submission.
Funding
Funding provided by Marine Polymer Technologies, Inc., and the NIH/NIAMS supported Penn Center for Musculoskeletal Disorders Grant (5P30AR069619).
Study approved by: University of Pennsylvania IACUC #806378
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Nuss, C.A., Huegel, J., Finkielsztein, S. et al. Liquid Poly-N-acetyl Glucosamine (sNAG) Improves Achilles Tendon Healing in a Rat Model. Ann Biomed Eng 49, 515–522 (2021). https://doi.org/10.1007/s10439-020-02711-w
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DOI: https://doi.org/10.1007/s10439-020-02711-w