Role for complement in mediating intestinal nitric oxide synthase-2 and superoxide dismutase expression.
Inducible nitric oxide synthase (iNOS) and superoxide dismutase (SOD) play an important role in the pathology of ischemia-reperfusion. This study sought to determine if the proinflammatory effects of complement modulate iNOS and SOD in the rat after gastrointestinal ischemia and reperfusion (GI/R). An inhibitory or noninhibitory anti-complement component 5 (C5) monoclonal antibody (18A or 16C, respectively) was administered before GI/R. RT-PCR revealed a significant increase in intestinal iNOS mRNA compared with sham after GI/R that was attenuated significantly by 18A. Immunohistochemistry demonstrated increased iNOS protein expression within the intestinal crypts after GI/R. Cu/Zn SOD (mRNA and protein) was unaffected by GI/R, whereas Cu/Zn SOD activity was reduced significantly. Mn SOD protein expression was decreased significantly by GI/R. Anti-C5 preserved Cu/Zn SOD activity and Mn SOD protein expression. Staining for nitrotyrosine showed that anti-C5 treatment reduced protein nitration in the reperfused intestine. Immunohistochemistry demonstrated prominent phosphorylated (p) inhibitory factor-kappaB (IkappaB)-alpha staining of intestinal tissue after GI/R, whereas anti-C5 reduced p-IkappaB-alpha expression. These data indicate that complement may mediate tissue damage during GI/R by increasing intestinal iNOS and decreasing the activity and protein levels of Cu/Zn SOD and Mn SOD, respectively.
Montalto
Michael C
MC
Center for Experimental Therapeutics and Reperfusion Injury, Dept. of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA.
Hart
Melanie L
ML
Jordan
James E
JE
Wada
Koichiro
K
Stahl
Gregory L
GL
D000818:Animals; D003182:Complement C5 / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000276:immunology; D020672:I-kappa B Proteins / Q000378:metabolism; D007375:Interleukin-1 / Q000235:genetics; D007422:Intestines / Q000201:enzymology* / Q000276:immunology; D000072000:NF-KappaB Inhibitor alpha; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D026361:Reactive Nitrogen Species / Q000378:metabolism; D015427:Reperfusion Injury / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
D003182:Complement C5; D020672:I-kappa B Proteins; D007375:Interleukin-1; C000606206:Nfkbia protein, rat; D012333:RNA, Messenger; D026361:Reactive Nitrogen Species; D000072000:NF-KappaB Inhibitor alpha; D014443:Tyrosine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D013482:Superoxide Dismutase