Endogenous Interleukin-10 Contributes to Wound Healing and Regulates Tissue Repair

Introduction: Interleukin-10 (IL-10) is essential in fetal regenerative wound healing and likewise promotes a regenerative phenotype in adult dermal wounds. However, the role of endogenous IL-10 in postnatal dermal wound healing is not well-established. We sought to determine the function of endogenous IL-10 in murine full thickness excisional wounds that are splinted to prevent contracture and mimic human patterns of wound closure.

Methods: Full-thickness excisional wounds were made in wildtype (WT) and IL-10^-/- mice on a C57BL/6J background (F/M, 8 wk old). In a subset of wounds, contraction was prevented by splinting with silicone stents (stenting) and maintaining a moist wound microenvironment using a semiocclusive dressing. Wounds were examined for re-epithelialization, granulation tissue deposition, and inflammatory cell infiltrate at day 7 and fibrosis and scarring at day 30 postwounding.

Results: We observed no difference in wound healing rate between WT and IL-10^-/- mice in either the stented or unstented group. At day 7, unstented IL-10^-/- wounds had a larger granulation tissue area and more inflammatory infiltrate than their WT counterparts. However, we did observe more F4/80⁺ cell infiltrate in stented IL-10^-/- wounds at day 7. At day 30, stented wounds had increased scar area and epithelial thickness compared to unstented wounds.

Conclusions: These data suggest that endogenous IL-10 expression does not alter closure of full thickness excisional wounds when wound hydration and excessive contraction of murine skin are controlled. However, the loss of IL-10 leads to increased inflammatory cell infiltration and scarring. These new findings suggest that IL-10 contributes to the regulation of inflammation without compromising the healing response. These data combined with previous reports of increased rates of healing in IL-10^-/- mice wounds not controlled for hydration and contraction suggest an important role for murine wound healing models used in research studies of molecular mechanisms that regulate healing.