Effects of keratinocyte growth factor on intra-alveolar surfactant fixed in situ: Quantitative ultrastructural and immunoelectron microscopic analysis.
Quantitative (immuno) transmission electron microscopy using design-based stereology was performed on specimens collected by means of systematic uniform random sampling of rat lungs, which were fixed by vascular perfusion to stabilize intra-alveolar surfactant in situ. This procedure ensures that the data recorded are representative of the whole organ. Ultrathin sections of specimens embedded at low temperature in Lowicryl HM20 were labeled by indirect immuno-gold staining for surfactant protein A. We observed that, 3 days after treatment of lungs in vivo with truncated keratinocyte growth factor (DeltaN23-KGF), a potent mitogen of alveolar epithelial type II cells, surfactant protein A associated with the tubular myelin fraction of intra-alveolar surfactant was increased by 47% in comparison with buffer-treated control lungs. Despite the marked type II cell hyperplasia, the relative amount of ultrastructural surfactant subtypes was not significantly affected. Because surfactant protein A reduces the sensitivity to inhibition of the biophysical activity of surfactant by exudating plasma proteins, we propose that pretreatment of lungs with DeltaN23-KGF ameliorates adverse effects observed in acute lung injury following, for example, ischemia and reperfusion.
Fehrenbach
Heinz
H
Clinical Research Group "Chronic Airway Diseases", Clinic of Internal Medicine (Respiratory Medicine), Philipps-University Marburg, Baldingerstrasse, Marburg Germany. heinz.fehrenbach@staff.uni-marburg.de
Fehrenbach
Antonia
A
Dietzel
Erik
E
Tschernig
Thomas
T
Krug
Norbert
N
Grau
Veronika
V
Hohlfeld
Jens M
JM
D000818:Animals; D005260:Female; D051523:Fibroblast Growth Factor 7 / Q000494:pharmacology*; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D016253:Microscopy, Immunoelectron / Q000379:methods*; D009186:Myelin Sheath / Q000187:drug effects / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D037662:Pulmonary Surfactant-Associated Protein A / Q000187:drug effects / Q000378:metabolism; D037701:Pulmonary Surfactant-Associated Protein B / Q000187:drug effects / Q000378:metabolism; D011663:Pulmonary Surfactants / Q000378:metabolism*; D051381:Rats; D011914:Rats, Inbred BN; D015427:Reperfusion Injury / Q000517:prevention & control; D012128:Respiratory Distress Syndrome / Q000517:prevention & control; D016707:Tissue Fixation / Q000379:methods
D037662:Pulmonary Surfactant-Associated Protein A; D037701:Pulmonary Surfactant-Associated Protein B; D011663:Pulmonary Surfactants; D051523:Fibroblast Growth Factor 7