Injection of prostaglandin F2α into the bronchial artery in sheep increases the pulmonary vascular permeability to protein

Lung injury and oedema following smoke inhalation are associated with eicosanoid release and the injury is heavily influenced by the tracheobronchial circulation. We hypothesized that injection of a vasoactive eicosanoid, prostaglandin F2alpha (PGF2α), into the tracheobronchial circulation would induce a permeability leak in that circulation as measured in lung lymph flow and protein content. PGF2α when injected into the bronchial artery increased lung lymph flow, protein content and lymph protein flux (protein times flow). The increase in lymph to plasma protein concentration after injection of PGF2α is consistent with an increase in vascular protein permeability since an increase in pressure alone would cause an increase in fluid flow in excess of protein with a fall in protein concentration. Ligation of the bronchial artery 3 min after injection of the PGF2α largely prevented the late changes suggesting that the protein leak into the lymph was from the bronchial arteries.