title: Differential cytokine response in interstitial fluid in skin and serum during experimental inflammation in rats.
abstract: Tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) are important mediators produced during inflammation. We hypothesized that the pro-inflammatory cytokine response in the interstitial fluid (IF) is different from that in serum, and we aimed at quantifying the amount of TNF-alpha and IL-1beta in the IF. By centrifugation of rat skin at < 424 g pure IF is extracted. Using ELISA such fluid was analysed for cytokines in back and/or paw skin of pentobarbital-anaesthetized rats, after either induction of endotoxaemia or ischaemia-reperfusion (I/R) injury. During endotoxaemia, TNF-alpha increased in the IF from 0 in control to 640 +/- 100 pg ml(-1) (mean +/-s.e.m.) after 90 min, with the serum concentration being 5-10 times higher at all time points. The response pattern of IL-1beta after lipopolysaccharide (LPS) challenge differed greatly from that of TNF-alpha with a large increase in IF from 390 +/- 90 to 28 000 +/- 1500 pg ml(-1) after 210 min, and a significantly smaller increase in serum (600 +/- 45 pg ml(-1)). During reperfusion of the hind paw after 2 h of ischaemia, there was a gradual increase of TNF-alpha in both IF of the paw skin and serum after 3 min of reperfusion. Both declined after 20 min. The pattern for IL-1beta differed, increasing significantly less in serum (25 +/- 15 pg ml(-1) after 20 min of reperfusion) than in the IF (1100 +/- 200 pg ml(-1)). Immunostaining of the inflamed tissues showed increased expression of the two cytokines in cells of both epidermis and dermis compared to controls. Subdermal injections of TNF-alpha and IL-1beta at the same concentrations found in IF after LPS infusion affected interstitial fluid pressure significantly. Local TNF-alpha production dominates after I/R injury, whereas in endotoxaemia systemic production predominates. For IL-1beta local production dominates in both conditions. Thus, there is a differential pattern of cytokine production and the current method allows the study of the role of cytokines in IF during different inflammatory reactions.
authors.affiliation: Department of Physiology, University of Bergen, Jonas Lies vei 91, N-5009 Bergen, Norway. torbjorn.nedrebo@fys.uib.no
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Nedrebø
authors.forename: Rolf K
authors.initials: RK
authors.lastname: Reed
authors.forename: Roland
authors.initials: R
authors.lastname: Jonsson
authors.forename: Ansgar
authors.initials: A
authors.lastname: Berg
authors.forename: Helge
authors.initials: H
authors.lastname: Wiig
mesh_terms: D000818:Animals; D001415:Back; D019446:Endotoxemia / Q000150:complications*; D045604:Extracellular Fluid / Q000378:metabolism; D005260:Female; D006614:Hindlimb / Q000098:blood supply*; D007249:Inflammation / Q000209:etiology / Q000378:metabolism*; D007375:Interleukin-1 / Q000097:blood / Q000378:metabolism*; D011312:Pressure; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000150:complications*; D012867:Skin / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D007375:Interleukin-1; D014409:Tumor Necrosis Factor-alpha