Upregulation of cyclooxygenase-II gene and PGE2 production of peritoneal macrophages in diabetic rats.
BACKGROUND
Patients with diabetes mellitus have increased risk of developing infectious complications following trauma and surgery. Recent studies have attributed altered immunoinflammatory responses of these patients as the cause of the underlying pathophysiology. This study was designed to investigate the effect of hyperglycemia on tissue-fixed macrophages (MO) PGE2 production.


METHODS
Experimental hyperglycemia was induced in Sprague-Dawley rats by intraperitoneal injection of streptozotocin (65 mg/kg). Peritoneal MO were harvested and stimulated with Escherichia coli LPS (1 ng to 1 microg/ml). COX-2 mRNA expression was measured by RT-PCR with specific primers. PGE2 production by peritoneal MO was determined by ELISA. In addition, the effect of hyperglycemia on NFkappaB activation and pro-inflammatory cytokines induced by LPS were studied on RAW 264.7 cells cultured in media with either 5.5 mm or 25 mm of glucose.


RESULTS
LPS stimulation induced a dose-dependent response of PGE2 production and COX-2 mRNA expression. MO from diabetic animals produced more COX-2 mRNA and PGE2 than the control animals. LPS stimulation induced NFkappaB activation that was attenuated by hyperglycemia in RAW cells. Similarly, hyperglycemia reduced the production of TNF and IL-6.


CONCLUSIONS
Our data suggest that hyperglycemia alters LPS-stimulated macrophage responses by augmenting anti-inflammatory activities such as PGE2. In addition, hyperglycemia also reduces NFkappaB activity and NFkappaB-dependent cytokines production.
Lo
Chong-Jeh
CJ
Department of Surgery, National Cheng Kung University, Tainan, Taiwan. jehlo@mail.ncku.edu.tw
D000818:Animals; D051546:Cyclooxygenase 2; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology / Q000378:metabolism*; D015232:Dinoprostone / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli; D015971:Gene Expression Regulation, Enzymologic; D006943:Hyperglycemia / Q000378:metabolism*; D008070:Lipopolysaccharides; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D008297:Male; D016328:NF-kappa B / Q000378:metabolism; D010537:Peritoneum / Q000166:cytology; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone