To examine the effects of peptidyl membrane interactive molecule D4B in a murine model of lethal burn wound infection.
Four experiments were performed: (1) growth inhibition assays of Pseudomonas aeruginosa treated with D4B, 0 to 100 µmol/L; (2) in vitro coculture of bone marrow cells with D4B, 0 to 100 µmol/L; (3) D4B treatment survival studies after burn injury only or burn wound infection in mice; and (4) peripheral white blood cell count, burn wound tissue bacterial culture, and burn wound morphological analysis at days 1, 2, and 3 after injury.
University medical center laboratory.
Groups of B6D2F1 male mice (20 each) were studied.
Full-thickness scald burn, 15% of total body surface area, with P aeruginosa topical infection, and subeschar injections of D4B at 200 µg or 0.25 mL of placebo per mouse at 2 and 24 hours after injury.
Main Outcome Measures
Animal survival after thermal burn wound bacterial infection, circulating leukocyte numbers, in vitro clonal cell culture of granulocyte-macrophage progenitor cells, and wound histopathological analysis.
The survival rate in the D4B-treated group was nearly 2-fold greater than that in controls (P<.01) during 14 days of study. Bacterial quantitative wound cultures disclosed significant reductions in bacterial numbers at days 1, 2, and 3 in D4B-treated animals as compared with controls (P<.05 to <.01). D4B induced a dose-dependent inhibition of bacterial cell growth when added to in vitro P aeruginosa cultures (P<.01). Granulocyte-macrophage progenitor cell growth in culture was not altered by D4B treatment. D4B-treated animals displayed no signs of toxic effects or impairment in wound healing.
The peptidyl membrane interactive molecule D4B had the ability to improve survival after gram-negative burn wound sepsis via direct antimicrobial effects. Peptidyl membrane interactive molecules may offer the potential of alternative treatments to standard topical agents or in patients with drug-resistant microbes.