THE PRODUCTION OF EXPERIMENTAL CHOLECYSTITIS BY ENDOTOXIN

Acute acalculous cholecystitis (AAC) is a severe inflammatory disorder of the gallbladder. It occurs primarily in patients acutely ill from other disorders and is related to sepsis and shock. We previously found that platelet-activating factor (PAF), a phospholipid autacoid purported to be a mediator of the shock response, produced AAC. This study was performed to determine the effect of intravenous lipopolysaccharide (LPS) on feline gallbladders. Anesthetized cats underwent LPS administration with and without administration of a cyclooxygenase inhibitor and PAF antagonist. Gallbladder inflammation was evaluated by quantitation of luminal water transport and tissue myeloperoxidase levels. In an attempt to understand the mechanisms of the response, gallbladder perfusate and tissue prostanoid and PAF levels were quantitated as were serum PAF levels. LPS administration resulted in alteration of the normal absorptive pattern of the gallbladder mucosa to exsorption of fluid into the gallbladder lumen, increased tissue myeloperoxidase levels and increased serum PAF levels. This was associated with increased gallbladder tissue and perfusate prostanoid levels and increased perfusate PAF levels. Indomethacin prevented the pro-inflammatory changes in the gallbladder produced by LPS. The PAF antagonist, alprazolam, increased gallbladder prostanoid production when administered alone and with LPS. The administration of LPS resulted in the production of acute changes in the gallbladder consistent with cholecystitis. These changes being prevented by a cyclooxygenase inhibitor suggests that development of AAC may be related to the release of systemic and local pro-inflammatory substances.