Evaluation of lymphatic regeneration in rat incisional wound healing and its use in wound age estimation

Abstract Objective During the wound healing process, lymphatic regeneration in the injured skin has not been fully investigated. This work was designed to study the regeneration of lymphatic vessels in rat incisional wounds in relation to the duration after the wound infliction. Material and methods We studied the regeneration of lymphatic vessels in the rat skin incisional wounds (sutured and unsutured) by immunohistochemistry using an antibody against D2-40, a marker of lymphatic endothelium. Results Lymphatic vessels were detectable transiently at the wound edge and depth from day 3 till day 7, and none on day 10 in sutured wounds; and from day 5 till day 10, and none on day 14 in unsutured wounds. On the other hand, the center of the wound area did not show any evidence of lymphatic regeneration up to 60 days after the skin incision, regardless of presence/absence of sutures. Meanwhile, the regenerating blood vessels started to appear in the granulation tissue as early as day 2 in sutured wounds and day 3 in unsutured wounds. Conclusion Lymphatic elements appear transiently in the wound edge, concurrent with the appearance of blood vessels but regress earlier. Identification of lymphatic vascular channels in the region of the wound may help to estimate the wound age in the early days after the injury. At later time points in the regeneration process, it may help to recognize the injured area, being the area where the dermis and subcutaneous tissue are devoid of lymphatics.