The kinetics of macrophage and surfactant replacement in hamster lung following bronchopulmonary lavage

The Clara cell and pulmonary surfactant: a study using selective chemical ablation

Administration of 3-hydroxymethylfuran-N-ethylcarbamate (HFC) to female hamsters via the jugular vein under pentobarbitone anaesthetic at 20 mg per kg body weight produced pronounced necrosis of the Clara cells without apparent morphological effect on other cell types as judged by transmission electron microscope examination. The surfactant material recoverable by minimal lavage followed by purification by sucrose gradient ultracentrifugation increased, reaching a maximum around 48 h after treatment. At this time static pressure/volume measurements on isolated lungs indicated an increase in airway surface compliance. Lavageable surfactant phospholipid composition was examined by 31P nuclear magnetic resonance (n.m.r.). The distribution of phospholipids between the various classes was unchanged by HFC treatment. No change in the total lung surfactant pool size was seen. These results are discussed in relation to the possible roles of the Clara cell in influencing airway surfactant levels.

Increased recovery of neutrophils, macrophages and lymphocytes following repeated lavage of sheep lung in vivo

The effect of bronchopulmonary lavage of adult sheep with sterile saline on the number and type of cells recovered in subsequent lavages was studied. We found that neutrophils increased from negligible numbers to 66 +/- 29 X 10(6) per lung (p less than 0.05), one day following the initial lavage. Alveolar macrophages also increased, from 39 +/- 4 to 69 +/- 13 X 10(6) per lung (p less than 0.005) 4 days following the initial lavage. Lymphocytes increased from 14 +/- 2 to 56 +/- 17 X 10(6) per lung (p less than 0.05) after 1 day, and remained elevated through 4 days. Numbers of all three cell types returned to baseline by the 7th day. No changes in numbers of neutrophils or macrophages were noted when the contralateral lung was lavaged 1 or 3 days after the original lavage. Cell types in peripheral blood were unchanged 24 hours after the initial lavage. We conclude that factors released in response to lavage act locally to produce increases in neutrophils, lymphocytes and macrophages which return to normal after 7 days.

The reversible detachment and deposition of surfactant and of pulmonary macrophages during bronchopulmonary lavage in the rat

A procedure is described for carrying out repetitive bronchopulmonary lavage in the rat, in which a given volume of lavage fluid is introduced into the lungs from a reservoir and then withdrawn from the lungs back into the reservoir, the process being repeated a number of times. During this procedure there is a net release of endogenous surfactant and macrophages from the lungs. [14C] pulmonary surfactant was prepared from rats previously injected intravenously with [1-14C] palmitate, and pulmonary macrophages labelled with 85Sr were prepared from rats which had received by intratracheal injection a suspension of fused clay particles labelled with 85Sr. It was shown by carrying out repetitive bronchopulmonary lavage with 0.15M-NaCl containing either exogenous [14C]-surfactant or [85Sr]-macrophages that the release of endogenous surfactant and macrophages from the lung into the lavage fluid occurred concomitantly with the retention within the lung of radioactive exogenous surfactant and macrophages from the lavage fluid. It is concluded that the process of surfactant and macrophage detachment during bronchopulmonary lavage is reversible and that the exchange processes are of substantial magnitude.

The behaviour of uranium-233 oxide and uranyl-233 nitrate in rats

233UO2 and 233UO2(NO3)2 in aqueous suspension have been administered to rats by pulmonary intubation. The 233U associated with the fraction of the 233UO2 less than 4 nm in diameter translocates from lungs to blood at the same rapid rate as 233U from 233UO2(NO3)2. Identical reactions with blood plasma and lung fluid were observed whether the 233U was administered as less than 4 nm 233UO2 particles or 233UO2(NO3)2. It is suggested that oxidation of UO2 to UO3 occurs followed by the formation of uranyl ion. In blood plasma, approximately 50 per cent of the 233U is bound to transferrin, 25 per cent to citrate and 25 per cent on bicarbonate.