Attenuating burn wound inflammation improves pulmonary function and survival in a burn-pneumonia model

Objective. We previously showed that topical inhibition of inflammatory signaling in burn wounds reduced systemic inflammatory response and burn-induced pulmonary inflammation. We hypothesized that this topical intervention would attenuate burn-induced lung injury, improve pulmonary function, protect lungs from bacterial invasion, and reduce mortality. Design: Controlled, in vivo, laboratory study. Setting: University laboratory. Subjects: Female mice, 8-10 wks old. Interventions: Animals received 30% total body surface area burn followed by topical application of a specific inhibitor of p38 mitogen-activated protein kinase, a key inflammatory signaling pathway, or vehicle to the wound. Twenty-four hours after injury, pulmonary collagen deposition and pulmonary function were assessed. One day postburn, some of the animals received intratracheal instillation of Klebsiella pneumoniae and were subsequently monitored for 7 days. Measurements and Main Results: Topical inhibition of p38 mitogen-activated protein kinase significantly decreased pulmonary collagen deposition and prevented a decline in pulmonary function at 1 day after burn injury. Compared with sham controls, animals with burn injury had a significantly higher mortality in response to intratracheal bacterial challenge. Application of p38 mitogen-activated protein kinase inhibitor to the burn wound attenuated pulmonary neutrophil infiltration and reduced the mortality rate to a level experienced by sham controls. Conclusions: Inflammatory source control in burn wounds with topical p38 mitogen-activated protein kinase inhibition attenuates acute lung injury, avoids pulmonary dysfunction, protects lungs from bacterial challenge, and improves survival.