The Effect of Local and Systemic Irradiation on Impairment of Wound Healing in Mice

Abstract

These experiments were designed to quantify the impact of local or systemic irradiation on the healing of full-thickness skin wounds in mice. Mice received total-body hemibody, or skin irradiations, prior to wounding. Wound tensile strength measured on day 14 was used as an end point. The dose to achieve an isoeffect of 40% of the tensile strength of the wounded controls was 13 Gy less for the total-body exposure than for local skin irradiation. Histological observation showed markedly fewer inflammatory cells in the wounded skin sections from total-body and hemibody-irradiated mice compared with those receiving only skin irradiation. These data demonstrate that the healing response in irradiated skin is dependent upon the extent of hematopoietic suppression and that at low doses this determines the outcome rather than damage to fixed target cells such as dermal fibroblasts, which are relatively resistant to radiation.

Vascularization in the transition area between free grafted soft tissues and pre‐irradiated graft bed tissues following preoperative radiotherapy in the head and neck region

“…1,2,19À23 Reasons for the discrepancies may be variations in the total radiation dose and in different time intervals between radiotherapy and surgery. 24 To date, there have been no reports on histomorphometric analyses of the vascularization pattern of the transition area between irradiated graft bed and grafted tissue. Profound knowledge of the healing processes, in particular of the neovascularization pattern, may enable us to predict the critical time interval until a free flap is adequately perfused from the graft bed.…”

“…24,33,34 The reduced mechanical wound strength is partly caused by radiation-induced reduction of collagen I expression in the fibroblasts during the proliferation phase. 24,35,36 Regarding the vascularization in the irradiated graft bed, a significant intima degeneration with apoptosis of the intima cells and a media fibrosis was proven after preoperative radiotherapy. 37,38 To date there have been no studies on the vascularization of free vascular grafts in the irradiated graft bed taking into account the preoperative irradiation dose and the interval between radiotherapy and grafting.…”

“…7 To date it has been possible to prove that radiotherapy in the proliferation phase leads to reduced endothelial and fibroblast proliferation and to reduced wound contraction and collagen formation. 24,29À32 Damage of the cellular elements involved in wound healing results in a reduction of collagen I expression through fibroblasts during the proliferation phase of irradiation-induced inflammation. 24,33,34 The reduced mechanical wound strength is partly caused by radiation-induced reduction of collagen I expression in the fibroblasts during the proliferation phase.…”

“…24,29À32 Damage of the cellular elements involved in wound healing results in a reduction of collagen I expression through fibroblasts during the proliferation phase of irradiation-induced inflammation. 24,33,34 The reduced mechanical wound strength is partly caused by radiation-induced reduction of collagen I expression in the fibroblasts during the proliferation phase. 24,35,36 Regarding the vascularization in the irradiated graft bed, a significant intima degeneration with apoptosis of the intima cells and a media fibrosis was proven after preoperative radiotherapy.…”

Topical Application of Hesperidin, a Citrus Bioflavanone Accelerates Healing of Full Thickness Dermal Excision Wounds in Mice Exposed to 6 Gy of Whole Body Γ-Radiation

“…The fibroblasts also secrete different angiogenic factors including VEGF, transforming growth factor-β (TGF-β) and Platelet Derived Growth Factor (PDGF), which are the involved in the formation of new blood vessels during tissue repair [56] and irradiation will negatively affect these processes due fibroblast killing [47]. Radiation has been found to adversely affect the fibroblasts and endothelial cells due to bone marrow depression and in fact radiation has been reported to diminish hematopoiesis in a dose-and time-dependent manner [14,[57][58][59]. A similar effect cannot be ruled out in the present study where whole body of the animal has been irradiated during the exposure.…”