Systemic inflammatory response in rats with explosive wound

Abstract

Aim. To evaluate the temporal changes in circulating cytokines rallying systemic inflammatory response after a blast injury.Material and Methods. Experiments were performed on 60 male Wistar rats (50 rats with blast-related soft tissue injury of the thigh and 10 intact rats). Blast injury was modeled under general anaesthesia using grater firecrackers stuffed with a pyrotechnic mixture. After 3, 7, 14 and 28 days post injury, we carried out a gross examination of the wound and its drainage, measured wound area, assessed local oedema severity, and evaluated serum potassium, myoglobin TNF-α, IL-1β, IL-6, and IL-10.Results. Three to seven days post injury, therewas abundant serous and purulent exudate and pronounced local edema without considerable changes in the wound area. Serum myoglobin and potassium were raised 2.2-2.6-fold and 1.3-fold, respectively (p < 0.05); in addition, we documented the elevation of a major pro-inflammatory cytokine IL-1β. Fourteen days post injury, wound area reduced by 24%, (p < 0.05) along with the decreased wound drainage and local edema of the injured area. Although the levels of serum myoglobin and pro-inflammatory cytokines (in particularIL-6) lowered, they were still significantly higher as compared with the intact rats. Twenty eight days post injury, fibrosis has been completed, epithelialization occurred and only a small scab remained on the wound surface. Yet, serum IL-1β still was 1.3-fold higher than in the intact animals (p < 0.05), albeit IL-6 and TNF-α returned to the reference values. The concentration of anti-inflammatory cytokine IL-10 reached its maximum values relative to the control (3.9-fold, p < 0.05) to the 14th day post injury that was followed by a considerable reduction (though not reaching the reference values) by the period of scar formation.Conclusion. Blast injury in rats is accompanied by a dysregulated balance between pro-inflammatory and anti-inflammatory cytokines throughout all regeneration phases.