Radiation Combined Injury Models to Study the Effects of Interventions and Wound Biomechanics

• Published in: Radiation research Vol. 182; no. 6; pp. 640 - 652
• Main Authors: Zawaski, Janice A., Yates, Charles R., Miller, Duane D., Kaffes, Caterina C., Sabek, Omaima M., Afshar, Solmaz F., Young, Daniel A., Yang, Yunzhi, Gaber, M. Waleed
• Format: Journal Article
• Language: English
• Published: United States The Radiation Research Society 01-12-2014; Radiation Research Society; Allen Press Inc
• Subjects: Animal models; Animals; Anti-Bacterial Agents - pharmacology; Anti-Infective Agents, Local - pharmacology; Antibiotics; Assessments; Biomechanical Phenomena - drug effects; Biomechanical Phenomena - radiation effects; Biomechanics; Body Weight - drug effects; Body Weight - radiation effects; Casualties; Closures; Disease Models, Animal; Erythrocytes; Exposure; Injuries; Irradiation; Male; Mechanical Phenomena; Mice; Physical trauma; Platelet Count; Platelets; Radiation dosage; Radiation injuries; Radiation Injuries, Experimental - blood; Radiation Injuries, Experimental - pathology; Radiation Injuries, Experimental - physiopathology; Radiation Injuries, Experimental - therapy; Rats; REGULAR ARTICLES; Skin - drug effects; Skin - pathology; Skin - physiopathology; Skin - radiation effects; Space life sciences; Survival; Survival Analysis; Wound healing; Wound Healing - drug effects; Wound Healing - radiation effects; Wounds
• ISSN: 0033-7587; 1938-5404
• DOI: 10.1667/RR13751.1

In the event of a nuclear detonation, a considerable number of projected casualties will suffer from combined radiation exposure and burn and/or wound injury. Countermeasure assessment in the setting of radiation exposure combined with dermal injury is hampered by a lack of animal models in which the effects of interventions have been characterized. To address this need, we used two separate models to characterize wound closure. The first was an open wound model in mice to study the effect of wound size in combination with whole-body 6 Gy irradiation on the rate of wound closure, animal weight and survival (morbidity). In this model the addition of interventions, wound closure, subcutaneous vehicle injection, topical antiseptic and topical antibiotics were studied to measure their effect on healing and survival. The second was a rat closed wound model to study the biomechanical properties of a healed wound at 10 days postirradiation (irradiated with 6 or 7.5 Gy). In addition, complete blood counts were performed and wound pathology by staining with hematoxylin and eosin, trichrome, CD68 and Ki67. In the mouse open wound model, we found that wound size and morbidity were positively correlated, while wound size and survival were negatively correlated. Regardless of the wound size, the addition of radiation exposure delayed the healing of the wound by approximately 5–6 days. The addition of interventions caused, at a minimum, a 30% increase in survival and improved mean survival by ∼9 days. In the rat closed wound model we found that radiation exposure significantly decreased all wound biomechanical measurements as well as white blood cell, platelet and red blood cell counts at 10 days post wounding. Also, pathological changes showed a loss of dermal structure, thickening of dermis, loss of collagen/epithelial hyperplasia and an increased density of macrophages. In conclusion, we have characterized the effect of a changing wound size in combination with radiation exposure. We also demonstrated that the most effective interventions mitigated insensible fluid loss, which could help to define the most appropriate requirements of a successful countermeasure.