Microbial Symbionts Accelerate Wound Healing via the Neuropeptide Hormone Oxytocin
(a) Direct microscopy of formalin-fixed, paraffinized wounded skin of aged Rag2–/– C57BL/6 mice (6 days post-wounding). Wound margins are delineated with yellow outlines. The healing time course is faster in mice receiving L. reuteri-primed Foxp3+ Tregs as evidenced by significantly reduced wound sizes in both male and female recipient mice. (b) Significantly advanced re-epithelialization of wounds of Rag2–/– mice after adoptive cell transfer of Foxp3+ cells from L. reuteri-treated donors. (c) Early granulation tissue in mice receiving Foxp3+ Tregs from untreated controls is characterized by minimal amount of collagen, and (d) abundant neutrophils with (e) small numbers of Foxp3+ lymphocytes. The granulation tissue of mice receiving L. reuteri-primed Tregs is more mature with (c) increased collagen deposition, and (d) occasional neutrophils and (e) increased accumulation of the transferred Foxp3+ cells lymphocytes. (LR Foxp3+GFP+ cells (n = 6), Untreated Foxp3+GFP+ cells (n = 5) for each gender.) b) Hematoxylin and Eosin. (b) Masson's Trichrome. (d) and (e) Immunohistochemistry: Diaminobenzidine chromogen, Hematoxylin counterstain. Scale bars (b) = 250 µm; (c), (d) and (e) = 50 µm.