Effect of Interleukin-10 Overexpression on the Properties of Healing Tendon in a Murine Patellar Tendon Model

Purpose Interleukin-10 (IL-10) is a potent anti-inflammatory cytokine shown to inhibit scar formation in fetal Wound healing. The role of IL-10 in adult tendon healing and scar formation. however, remains unknown. The objective of this study is to investigate the effect of IL-10 overexpression on the properties of adult healing tendon using a well-established murine model of tendon injury and a lentiviral-mediated method of IL-10 overexpression. Methods A Murine model of patellar tendon Injury Was used and animals divided into 3 groups. Mice received bilateral patellar tendon injections with a lentiviral vector containing an IL-10 transuene (n = 34) or no transg ene (n = 34). Control mice (n = 34) received injections of sterile saline. All animals then were subjected to bilateral, central patellar tendon injuries 2 days after injection and were killed at 5, 10. 21, and 42 days after injury. IL-10 content was analyzed by immunohistochemistry (n = 4/group). Tendon healing was evaluated by histology (n = 4/group) and biomechanical analysis (n = 10/group). Results Overexpression of IL-10 in patellar tendon wits confirmed after injection of the lentiviral vector. IL-10 immunostaining, was increased at day 10 in the IL-10 group relative to that in controls. Histologically, there was no significant difference in angular deviation between groups at day 21. but a trend toward decreased angular deviation in controls relative to that in empty vector group mice was seen at day 42. Biomechanically, the IL-10 group showed significantly increased maximum stress at day 42 relative to that in controls. Percent relaxation showed a trend toward an increase at day 10 and a significant increase at day 42 in the IL-10 group relative to that in controls. Conclusions This Study demonstrates Successful gene transfer of IL-10 into adult murine patellar tendon using a lentiviral vector. Although the effects of overexpression of IL-10 on adult tendon healing have not yet been fully elucidated. the current study may hell) to further clarify the mechanisms of tendon injury and repair. (J Hand Surg 2008;33A: 1843-1852. Copyright (c) 2008 by the American Society for Surgery of the Hand. All rights reserved.)