Acute lung injury is a common complication of
acute pancreatitis (AP) and contributes to the majority of AP-associated deaths. Although some aspects of AP-induced
lung inflammation have been demonstrated, investigation of resultant changes in lung function is limited. The aim of this study was to characterize
lung injury in
caerulein-induced AP. Male Sprague Dawley rats (n = 7-8/group) received 7
injections of
caerulein (50 μg/kg) at 12, 24, 48, 72, 96, or 120 hours before measurement of lung impedance mechanics. Bronchoalveolar lavage (BAL), plasma, pancreatic, and lung tissue were collected to determine pancreatic and lung measures of acute
inflammation. AP developed between 12 and 24 hours, as indicated by increased plasma
amylase activity and pancreatic
myeloperoxidase (MPO) activity,
edema, and abnormal acinar cells, before beginning to resolve by 48 hours. In the lung, MPO activity peaked at 12 and 96 hours, with BAL
cytokine concentrations peaking at 12 hours, followed by lung
edema at 24 hours, and BAL cell count at 48 hours. Importantly, no significant changes in BAL
protein concentration or arterial blood gas-pH levels were evident over the same period, and only modest changes were observed in respiratory mechanics.
Caerulein-induced AP results in minor
lung injury, which is not sufficient to allow
protein permeability and substantially alter respiratory mechanics.