Role of L-selectin in physiological manifestations after burn and smoke inhalation injury in sheep

The effects of a monoclonal antibody against L-selectin [leukoctye adhesion molecule (LAM)1-3] on microvascular fluid flux were determined in consciou s sheep subjected to a combined injury of 40% third-degree burn and smoke i nhalation. This combined injury induced a rapid increase in systemic prefem oral lymph flow (S(Q) over dot(lymph)) from the burned area and a delayed-o nset increase in lung lymph flow. The initial increase in S(Q)(lymph) was a ssociated with an elevation of the lymph-to-plasma oncotic pressure ratio; consequently, it leads to a predominant increase in the systemic soft tissu e permeability index (sPI). In an untreated control group, the increased sP I was sustained beyond 24 h after injury. Pretreatment with LAM1-3 resulted in earlier recovery from the increased sPI, although the initial responses in S(Q)(lymph) and sPI were identical to those in the nontreatment group. The delayed-onset lung permeability changes were significantly attenuated b y pretreatment with LAM1-3. These findings indicate that both leukocyte-dep endent and -independent mechanisms are involved in the pathogenesis that oc curs after combined injury with burn and smoke inhalation.