Thoracic duct ligation in the rat attenuates lung injuries in acute pancreatitis

In acute pancreatitis (AP), inflammatory cells and products disseminated in abdominal lymph and blood induce systemic inflammation. Interruption of abdominal lymph flow, and thereby reduction of lymphatic dissemination, could alter the course of the disease. Therefore, we investigated whether thoracic duct ligation (TDL) in a rat model of cerulein-induced AP results in reduced lung damage as a marker for reduction of systemic dissemination through the lymphatic system. Thirty-four male rats were assigned to TDL (TDL-rats, n=8), AP (AP-rats, n=8), TDL+AP (TDL+AP-rats, n=9) or sham TDL (Ctr-rats, n=9) groups. TDL and sham TDL were established first. Two days later, AP was induced in AP- and TDL+AP-rats by a series of subcutaneous injections of cerulein. Vehicle was injected in the same manner in Ctr- and TDL-rats as controls. Rats were sacrificed six hours after the end of the serial injections. Histological examination showed that AP-induced damage to the pancreas and ileum were similar in AP- and TDL+AP-rats whereas lung damage was less severe in TDL+AP-rats than in AP-rats. Assays demonstrated that: hepatic and pulmonary myeloperoxidase activities were increased in AP-rats but not in the TDL+AP-rats; more Il-6 was found in AP-rat than TDL+AP-rat lungs; and lung-lavage fluid from AP-rats yielded more angiopoietin-2 than TDL+AP-rats. In conclusion, prior TDL in the rat attenuates lung damage in acute pancreatitis.