An improved technique for repeated bronchoalveolar lavage and lung mechanics measurements in individual rats

• Published in: Respiratory physiology & neurobiology Vol. 154; no. 3; pp. 467 - 477
• Main Authors: Novák, Zoltán, Peták, Ferenc, Bánfi, Andrea, Tóth-Szuki, Valéria, Baráti, Levente, Kósa, Lajos, Bari, Ferenc, Székely, Edgár
• Format: Journal Article
• Language: English
• Published: Amsterdarm Elsevier B.V 01.12.2006; Elsevier
• Subjects: Acute Disease; Acute lung injury; Airway Resistance; Animals; Biological and medical sciences; Bronchoalveolar Lavage - methods; Bronchoalveolar Lavage Fluid - cytology; Cell Count; Feasibility Studies; Forced oscillations; Fundamental and applied biological sciences. Psychology; Lipopolysaccharide; Lipopolysaccharides; Lung - physiopathology; Lung Compliance; Lung Diseases - chemically induced; Lung Diseases - diagnosis; Lung Diseases - pathology; Lung Diseases - physiopathology; Male; Rats; Rats, Wistar; Respiration, Artificial; Respiratory Function Tests; Respiratory Mechanics; Surfactant washout; Vertebrates: respiratory system; Forced oscillations; Lipopolysaccharide; Acute lung injury; Surfactant washout; Rat; Acute; Lung; Rodentia; Surfactant; Respiratory system; Vertebrata; Mammalia; Bronchoalveolar lavage; Forced oscillation; Lesion
• ISSN: 1569-9048; 1878-1519
• DOI: 10.1016/j.resp.2005.12.004

Lung function and bronchoalveolar lavage (BAL) fluid are commonly analyzed to assess the severity of lung disease in sacrificed animals. The input impedance of the respiratory system ( Z rs) was measured and BAL fluid was collected in intubated, anesthetized, mechanically ventilated rats on three occasions 1 week apart. Measurements were performed in control animals (group C), while lung injury was induced in the other group (group LPS) by i.p. injection of lipopolysaccharide (LPS) before the second measurement. The airway resistance ( R aw), tissue damping ( G) and elastance ( H) were determined from the Z rs spectra. The total cell counts (TC) from 0.3- to 0.4-ml BAL fluid were also determined. R aw exhibited no significant change in either group C (−6.7 ± 3.6[S.E.]%) or LPS (−0.9 ± 3.7%). Reproducible G and H values were obtained in group C (2.5 ± 5.3%, −7.0 ± 4.4%), while G and H increased in group LPS (18.4 ± 6.5%, 14.9 ± 13.8%, p < 0.05). The changes in TC followed a similar pattern to those observed in G, with no change in group C (−7.9 ± 30%), but with a marked increase in group LPS (580 ± 456%, p < 0.05). The method devised for repeated BAL measurements in another group of rats without intubation and muscle relaxant resulted in similar results in BAL profile. We conclude that longitudinal follow-up of the airway and tissue mechanics and inflammatory cells in the BAL fluid are feasible in rats. The current method allows an early detection of lung injury, even in a relatively mild form.