The pathogenesis of L-arginine-induced acute necrotizing pancreatitis: inflammatory mediators and endogenous cholecystokinin.
This study was aimed at an assessment of the role of oxygen-derived free radicals, cytokines and endogenous cholecystokinin (CCK) in the pathogenesis of L-arginine (Arg)-induced acute pancreatitis in rat. We measured the levels of malonyl dialdehyde (MDA), glutathione peroxidase (GPx), catalase and superoxide dismutase (Mn- and Cu, Zn-SOD) in pancreatic tissue, the serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and CCK, and evaluated the protective effect of the xanthine oxidase inhibitor allopurinol and a novel CCK receptor antagonist KSG-504. Acute pancreatitis was induced in male Wistar rats by injecting 2x 250 mg/100 g body weight of Arg intraperitoneally in an 1-h interval, as a 20% solution in 0.15 M NaCl. Control rats received the same quantity of glycine. 200 mg x kg(-1) allopurinol 30 min before the first Arg treatment or 50 mg x kg(-1) KSG-504 30 min before and 6, 18 and 36 h after the first Arg injection was administered subcutaneously. Rats were killed at 6, 12, 24 and 48 h following Arg administration, and acute pancreatitis was confirmed by a serum amylase level elevation and typical inflammatory features observed microscopically. The serum level of amylase reached the peak level at 24 h after the Arg injection (30,800 +/- 3,813 versus 6,382 +/- 184 U x L(-1) in the control) and normalized at 48 h. The tissue concentration of MDA was significantly elevated at 24 h, and reached the peak value at 48 h (5.00 +/- 1.75 versus 0.28 +/- 0.05 nM x mg(-1) protein in the control). The catalase and Mn-SOD activities were significantly decreased throughout the study, while the GPx activity was significantly reduced at 6 and 12 h, and the Cu, Zn-SOD activity was significantly lower at 12 h after the Arg injection as compared with the controls. Both the TNF-alpha and the IL-6 levels were already elevated significantly at 12 h and peak at 24 h versus the controls (19.1 +/- 7.9 U x mL(-1) and 57.6 +/- 11.2 pg x mL(-1) versus 3.1 +/- 0.8 U x mL(-1) and 15.2 +/- 3.1 pg x mL(-1), respectively). No significant changes in plasma CCK levels were observed. Allopurinol treatment markedly reduced the serum amylase elevation (12.631 +/- 2.257 U x L(-1) at 24 h), prevented the increase in tissue MDA concentration (0.55 +/- 0.09 nM x mg(-1) protein at 48 h) and significantly ameliorated the pancreatic edema, necrosis and inflammation at 48 h after Arg administration. KSG-504 administration did not exert any beneficial effect on the development of histopathological changes neither modified the serum amylase or cytokine levels. Oxygen-derived free radicals and cytokines are involved, while endogenous CCK does not seem to play a role in the pathogenesis of Arg-induced acute pancreatitis.
Czakó
L
L
First Department of Medicine, Albert Szent-Györgyi Medical University, Szeged, Hungary.
Takács
T
T
Varga
I S
IS
Hai
D Q
DQ
Tiszlavicz
L
L
Hegyi
P
P
Mándi
Y
Y
Matkovics
B
B
Lonovics
J
J
D000493:Allopurinol / Q000494:pharmacology; D000681:Amylases / Q000097:blood; D000818:Animals; D001120:Arginine; D002374:Catalase / Q000378:metabolism; D002766:Cholecystokinin / Q000097:blood / Q000502:physiology*; D016207:Cytokines / Q000097:blood / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005979:Glutathione Peroxidase / Q000378:metabolism; D006727:Hormone Antagonists / Q000494:pharmacology; D018836:Inflammation Mediators / Q000502:physiology*; D008297:Male; D009281:Naphthalenes / Q000494:pharmacology; D010179:Pancreas / Q000473:pathology; D019283:Pancreatitis, Acute Necrotizing / Q000139:chemically induced* / Q000201:enzymology / Q000473:pathology; D010421:Pentanoic Acids / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000502:physiology; D013482:Superoxide Dismutase / Q000378:metabolism
D016207:Cytokines; D004791:Enzyme Inhibitors; D006727:Hormone Antagonists; D018836:Inflammation Mediators; D009281:Naphthalenes; D010421:Pentanoic Acids; D017382:Reactive Oxygen Species; C085253:KSG 504; D000493:Allopurinol; D002766:Cholecystokinin; D001120:Arginine; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D000681:Amylases