Direct administration of interleukin-1 and interferon-gamma to rat pancreas leads to the in vivo production of nitric oxide and expression of inducible nitric oxide synthase and inducible cyclooxygenase.
BACKGROUND
Proinflammatory cytokines may play a pivotal role in the pathogenesis of insulin-dependent diabetes mellitus (IDDM). In vitro, the formation of nitric oxide (NO) catalyzed by inducible NO synthase (iNOS) has been shown to be involved in the cytotoxic effects of cytokines on pancreatic beta cells. Cytokines have also been shown to cause the expression of inducible cyclooxygenase (COX-2) in isolated islets.


OBJECTIVE
To describe a novel in vivo model that allows investigation of the effects of direct cytokine administration to the pancreas.


RESULTS
By using this method, we demonstrate that administration of interleukin-1beta and interferon-gamma to rat pancreas results in the generation of NO in the treated pancreata as detected by NO trapping and electron paramagnetic resonance spectroscopy. Beta cells were identified as the source of the formed NO. Reverse transcription and polymerase chain reaction analyses showed that administration of cytokines to the pancreas leads to the expression of iNOS and COX-2 mRNA in the pancreas tissue as well as the islets isolated from such tissues. The compound phenyl N-tert-butylnitrone, which protects mice against streptozotocin-induced IDDM, inhibits NO formation and downregulates both iNOS and COX-2 mRNA levels.
Tabatabaie
T
T
Free Radical Biology and Aging Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA.
Vasquez
A M
AM
Moore
D R
DR
Floyd
R A
RA
Kotake
Y
Y
D000496:Alloxan / Q000494:pharmacology; D000818:Animals; D003497:Cyclic N-Oxides; D051546:Cyclooxygenase 2; D015870:Gene Expression; D007371:Interferon-gamma / Q000008:administration & dosage*; D007375:Interleukin-1 / Q000008:administration & dosage*; D007515:Islets of Langerhans / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics*; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000235:genetics*; D052247:Nitric Oxide Synthase Type II; D009589:Nitrogen Oxides / Q000494:pharmacology; D010179:Pancreas / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
D003497:Cyclic N-Oxides; D007375:Interleukin-1; D007527:Isoenzymes; D009589:Nitrogen Oxides; D012333:RNA, Messenger; D009569:Nitric Oxide; C029217:phenyl-N-tert-butylnitrone; D000496:Alloxan; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases