title: Isolation of rat trachea interstitial fluid and demonstration of local cytokine production in lipopolysaccharide-induced systemic inflammation.
abstract: Access to interstitial fluid from trachea is important for understanding tracheal microcirculation and pathophysiology. We tested whether a centrifugation method could be applied to isolate this fluid in rats by exposing excised trachea to G forces up to 609 g. The ratio between the concentration of the equilibrated extracellular tracer 51Cr-labeled EDTA in fluid isolated at 239 g and plasma averaged 0.94 +/- 0.03 (n = 14), suggesting that contamination from the intracellular fluid phase was negligible. The protein pattern of the isolated fluid resembled plasma closely and had a protein concentration 83% of that in plasma. The colloid osmotic pressure in the centrifugate in controls (n = 5) was 18.8 +/- 0.6 mmHg with a corresponding pressure in plasma of 22 +/- 1.5 mmHg, whereas after overhydration (n = 5) these pressures fell to 9.8 +/- 0.4 and 11.9 +/- 0.4 mmHg, respectively. We measured inflammatory cytokine concentration in serum, interstitial fluid, and bronchoalveolar lavage fluid in LPS-induced inflammation. In control animals, low levels of IL-1 beta, IL-6, and TNF-alpha in serum, trachea interstitial fluid, and bronchoalveolar lavage fluid were detected. LPS resulted in a significantly higher concentration in IL-1 beta and IL-6 in interstitial fluid than in serum, showing a local production. To conclude, we have shown that interstitial fluid can be isolated from trachea by centrifugation and that trachea interstitial fluid has a high protein concentration and colloid osmotic pressure relative to plasma. Trachea interstitial fluid may also reflect lower airways and thus be of importance for understanding, e.g., inflammatory-induced airway obstruction.
authors.affiliation: Dept. of Biomedicine, University of Bergen, Jonas Lies vei 91, N-5009 Bergen, Norway.
authors.forename: Elvira
authors.initials: E
authors.lastname: Semaeva
authors.forename: Olav
authors.initials: O
authors.lastname: Tenstad
authors.forename: Athanasia
authors.initials: A
authors.lastname: Bletsa
authors.forename: Eli-Anne B
authors.initials: EA
authors.lastname: Gjerde
authors.forename: Helge
authors.initials: H
authors.lastname: Wiig
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D002498:Centrifugation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D016207:Cytokines / Q000097:blood / Q000378:metabolism*; D004195:Disease Models, Animal; D045604:Extracellular Fluid / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides; D008297:Male; D009997:Osmotic Pressure; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D014132:Trachea / Q000378:metabolism* / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D016207:Cytokines; C508600:IL6 protein, human; D053583:Interleukin-1beta; D015850:Interleukin-6; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha