Perfluorocarbons are taken up by isolated type II pneumocytes and influence its lipid synthesis and secretion.
OBJECTIVE
Because alveoli fill with perfluorocarbons during liquid ventilation, an uptake of perfluorocarbons by type II pneumocytes can be postulated that might affect synthesis and secretion of pulmonary surfactant. The study was performed to answer the following questions: Do isolated type II pneumocytes take up perfluorocarbons? Do perfluorocarbons affect lipid synthesis of type II cells? Do perfluorocarbons change surfactant secretion of type II pneumocytes?


METHODS
Controlled experiments that used isolated type II pneumocytes.


METHODS
Experimental laboratory of a university hospital.


METHODS
Male Wistar rats.


METHODS
To study perfluorocarbon uptake, isolated type II cells were incubated with fluorescence-labeled perfluorocarbons and examined with a laser scanning microscope. The effect of perfluorocarbons on biosynthesis of phospholipids and triglycerides was measured by incubating cells that were pulse-labeled with [H]-palmitic acid for 30 secs, with two different perfluorocarbons (PF 5080 or RM 101) for 10 mins. The effect of perfluorocarbon incubation on lipid secretion was studied by transmission electron microscopy. To quantify secretion, adherent type II pneumocytes (containing radioactively labeled phospholipids) were incubated with perfluorocarbons, and extra- and intracellular radioactivity was measured.


RESULTS
We found a significant uptake of labeled perfluorocarbons into lamellar bodies within 10 mins. Both perfluorocarbon species significantly (p <.05) reduced the biosynthesis of phospholipids when compared with control. Perfluorocarbon incubation did not affect mitochondrial activity, tested by MitoTracker staining. Transmission electron microscopy revealed changes that suggest an increased secretion of surfactant by type II cells. Studies with radioactively labeled surfactant revealed a significantly (p <.01) higher amount of extracellular lipids after RM 101 and PF 5080 treatment (RM 101, 17 +/- 7.9%; PF 5080, 9 +/- 1.9%) compared with control (5.3 +/- 1.9%).


CONCLUSIONS
Our results suggest that perfluorocarbons are taken up by type II pneumocytes and cause an increased secretion of surfactant, despite a relative reduction in the synthesis of phospholipids.
Rüdiger
Mario
M
Clinic for Neonatology, Charité-Mitte, Humboldt-University Berlin, Germany.
Wissel
Heide
H
Ochs
Matthias
M
Burkhardt
Wolfram
W
Proquitté
Hans
H
Wauer
Roland R
RR
Stevens
Paul
P
Rüstow
Bernd
B
D000818:Animals; D005466:Fluorocarbons / Q000493:pharmacokinetics* / Q000494:pharmacology; D066298:In Vitro Techniques; D021061:Liquid Ventilation; D008297:Male; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D010743:Phospholipids / Q000096:biosynthesis*; D011650:Pulmonary Alveoli / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D011663:Pulmonary Surfactants / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014280:Triglycerides / Q000096:biosynthesis*
D005466:Fluorocarbons; D010743:Phospholipids; D011663:Pulmonary Surfactants; D014280:Triglycerides