Do peritoneal macrophages play an essential role in the progression of acute pancreatitis in rats?
BACKGROUND
Macrophages are considered to play an essential role in the events leading to systemic inflammatory response. Some are known to reside in the peritoneal cavity but there are no reports defining the participation of peritoneal macrophages (PMs) in the progression of acute pancreatitis.


OBJECTIVE
To clarify the role of PMs in the progression of acute pancreatitis.


METHODS
Acute pancreatitis was induced in rats from which macrophages other than PMs were greatly depleted, and in rats greatly depleted of macrophages including PMs. Macrophages were depleted by the injection of liposome encapsulated dichloromethylene bisphosphonate. After the induction of acute pancreatitis, local pancreatic inflammation, intraperitoneal inflammation and lung injury were compared between the 2 groups.


RESULTS
Local pancreatic inflammation did not differ between the 2 groups. However, intraperitoneal inflammation was clearly improved by the depletion of PMs. Serum cytokine level and lung injury were also improved by the depletion of PMs.


CONCLUSIONS
Peritoneal macrophages extend inflammation from the pancreas to the peritoneal cavity and subsequently induce lung injury in acute pancreatitis. Peritoneal macrophages play an essential role in the systemic inflammatory response and the progression of acute pancreatitis in the rat.
D000208:Acute Disease; D000818:Animals; D001201:Ascites; D002452:Cell Count; D004002:Clodronic Acid / Q000494:pharmacology; D016207:Cytokines / Q000032:analysis / Q000097:blood; D018450:Disease Progression; D007249:Inflammation / Q000276:immunology / Q000473:pathology; D008081:Liposomes; D008168:Lung / Q000473:pathology; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009504:Neutrophils / Q000166:cytology / Q000276:immunology; D009842:Oligopeptides / Q000097:blood; D010179:Pancreas / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D010195:Pancreatitis / Q000201:enzymology / Q000276:immunology / Q000473:pathology / Q000503:physiopathology*; D010529:Peritoneal Cavity / Q000473:pathology; D010533:Peritoneal Lavage; D009195:Peroxidase / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D016207:Cytokines; D008081:Liposomes; D009842:Oligopeptides; C080396:trypsinogen activation peptide; D004002:Clodronic Acid; D009195:Peroxidase