Abstract： Objective To investigate changes in the level of pre-B-cell colony-enhancing factor (PBEF) and its possible effect on acute lung injury (ALI) induced by seawater perfusion following open chest injury in dogs. Methods Sixteen healthy adult dogs were randomly divided into the pure open chest injury group (the control group) and seawater perfusion after injury group (later simply referred to as the seawater group). Plasma, bronchoalveolar lavage fluid (BALF) and lung tissue samples were collected before seawater-perfusion (0 h) and 6 h after seawater perfusion. The PBEF protein levels in plasma, BALF and lung tissue were measured with enzyme-linked immunosorbent assay (ELISA), immunohistochemistry and Western blot. The expression of mRNA synthesis of coding PBEF in lung homogenates was evaluated with real-time RT-PCR. Results Compared with those of the control animals, PBEF levels significantly increased in the animals of the seawater group [plasma: (3014.16±883.47) ng/L versus (1060.94±251.08) ng/L (P < 0.05); lung tissue(Western blot) :(0.233)±0.037) versus (0.1541±0.013) ng/L,with statistical significance (P <0.05); PBEF mRNA :5.27±0.05 versus 0.65±0.12, with obvious statistical significance (P < 0.05)]. PBEF levels were positively correlated with plasma osmotic pressure, with a relative coefficient of 0.744 (P<0.05). Conclusions Seawater perfusion could elevate the level of PBEF in animals with ALI induced by seawater perfusion following open chest injury, indicating that it might be closely related with the high permeability of seawater. PBEF was clearly involved in the pathophysiological process of ALI, and might be a novel biomarker which could be used to identify ALI induced by seawater perfusion.