Pancreatic acinar cells are the source of TNF-alpha during acute pancreatitis demonstration by in situ hybridization.

VACCARO MI; GRASSO D; ROPOLO A; FERRERIA M; LANOSA G

Chicago, IL, USA.

Congreso; American Pancreatic Association 1999 Meeting; 1999

American Pancreatic Association

Although TNF-a has been found in pancreatic tissue during acute pancreatitis, the actual source of cytoquines into the pancreas during the development of the disease has not been clearly established. In order to elucidate whether pancreatic acinar cell is able to express TNF-a in response to aggression, we studied TNF-a mRNA expression in healthy pancreas, in tissue from caerulein-induced pancreatitis and after lipopolysaccharide (LPS) treatment by in situ hybridization. One group on male Swiss mice weighing from 20 to 25 g was injected intraperitoneally 7 times with 50 mg caerulein/kg body weight with 1 hour interval. Another group was injected 4 times with 10 mg LPS/kg body weight. Control mice received sterile nonpyrogenic saline. Animals (3 per group) were killed by decapitation and the pancreas were removed. In specimens from normal pancreas, in situ hybridization with the digoxigenin-labeled antisense cRNA specific for TNF-a was negative; whereas strong expression was clearly observed in the cytoplasm around the nucleus of acinar cell from caerulein pancreatitis. Control hybridization with digoxigenin-labeled sense cRNA probe or with antisense cRNA in tissue sections previously treated with RNAsa A showed no signal. The expression  detected by in situ hybridization bore resemblance to mRNA levels showed by northern blot analysis. TNF-a mRNA appeared 15 min after cerulein injection, and was maximal 6 hours after cerulein first injection. LPS treatment also induced pancreatic expression of TNF-a, which was demonstrated in the cytoplasm around the nucleus of acinar cell by in situ hybridization. Our results indicated that pancreatic acinar cell is the source of TNF-a early in the development of acute pancreatitis and suggest that expression of the cytoquine is not constitutive but a part of a general response of the acinar cell to aggression.