Interactions of Systemic Immune Response and Local Wound Healing in Different Burn Depths: An Experimental Study on Rats

Abstract

This study aimed to clarify the local and systemic immune responses at different burn depths. Thirty female Sprague-Dawley rats were divided into three groups: full-thickness (F), partial-thickness (P), and Sham (S). Burns were induced on three separate areas on the dorsums of rats. Serum levels of interferon (IFN)-gamma; tumor necrosis factor-alpha; interleukin (IL)-1, IL-6, and IL-10 were measured once in controls and 1 hour after burn, 48 hours after burn, and 7 days after burn in F and P groups. Neutrophils, CD68-positive macrophages, HLA-DR-positive cells, and CD3-positive lymphocytes were graded semiquantitatively, and the wounds were examined once in shams and at 1 hour after burn, 48 hours after burn, and 7 days after burn in F and P groups. IL-6 levels were highest in F group, followed by P group 1 hour after burn. IFN-gamma levels were higher in the F group; IL-1 levels were higher in F and P groups at 1 hour after burn. Local accumulation of macrophages was similar in F and P groups. Lymphocytes were denser in P group at 1 hour after burn, and neutrophils were denser in F group at 7 days after burn. We suggest that early elevations of IL-6 and IFN-gamma prolong inflammation in full-thickness burns. Modulation of proinflammatory cytokines may improve burn wound treatment.