Bronchoalveolar lavage

Assessment of pathological and physiological changes in mouse lung through bronchoalveolar lavage

In animals, environmental exposure such as toxic chemicals and microorganisms or pathophysiological conditions in respiratory system could result in inflammatory response in their lungs. Bronchoalveolar lavage (BAL) is a procedure that can be used to collect samples from animal lungs to efficiently evaluate the immune response by examining both the compositions of cells and fluid from lavage. The profile of inflammatory cells in BAL provides a qualitative description of inflammatory response and the secretion in BAL fluid contains proteins of inflammatory mediators and albumin as a quantitative measurement of inflammation and tissue injury in the lungs. A consistent experimental approach on how to lavage mouse lungs and collect samples is important for a reproducible evaluation of pathological and physiological changes in mouse lung especially for the analysis of inflammation.

Automatic Adsorptive Isolation and Biophysical and Biochemical Characterization of the Surface Film of Human Bronchoalveolar Lavage Fluid

Lung surfactant is the surface active material of the lung alveoli that makes breathing possible. It consists of various amphiphilic components like phospholipids and surfactant proteins and can be isolated by bronchoalveolar lavage from the lungs. The function of the surfactant system of the lungs is dominated by the composition of the surface film. It is therefore highly probable that alterations of the lung surfactant in lung diseases are mostly reflected in the surface film of bronchoalveolar lavage fluid. The aim of the study was to investigate the possibility of isolating the native surface film of bronchoalveolar lavage (BAL) fluid with the high-performance surfactant purification apparatus HPS 1 from the technical as well as from the theoretical point of view.

Basically this method represents a technique for the high-performance purification of ordinary surfactants to remove surface-active impurities and to achieve “surface-chemically” pure solutions. After adsorption from bulk BAL fluid (within 30 min) and subsequent compression of the adsorbed layer (by an surface area ratio of 1 to 30) the adsorbed layer was aspirated (one cycle) and the aspirated solution collected. This procedure was repeated for 100 and 200 times. The collected fractions of the aspirated solutions (after 100 and 200 cycles), the original BAL fluid pool and the residual bulk phase were analysed for the total protein, total phospholipids and phospholipid subclasses. In addition, the dynamic surface tension of the solutions was measured. Generally, there was an increase of the protein and the phospholipid concentrations in the aspirated fractions by a factor 2 to 3 in comparison to the corresponding concentrations of the BAL fluid. Analysis of the phospholipid subclasses shows that the aspirated solutions, i. e. the surface film, contains phosphatidylcholine, phosphatidylglycerol and phosphatidylinositol. Phosphatidylethanolamine was not detected in the surface film. The percentage of phoshatidylglycerol in the surface film (100 cycles) was noticeably increased by 11.4% and 7.0%, respectively, in comparison to that of the BAL fluid. The equilibrium surface tension values of the aspirated solutions amounted to 37.5 and/or 40.3 mN/m (lavage fluid 1) and 38.6 and/or 40.2 mN/m (lavage fluid 2). The results prove that proteins and different phospholipids are integral parts of the surface film of BAL fluid and that this technique provides a new advantageous possibility for the isolation of native lung surfactant.

Quantitative Brewster angle microscopy of the surface film of human broncho-alveolar lavage fluid

The morphology, thickness and surface pressure of the surfactant film of broncho-alveoalar lavage (BAL) fluid from patients with sarcoidosis were investigated during spontaneous adsorption of the BAL's surface active material at the air/aqueous buffer interface at 37 degrees C. The biochemical parameters of the BAL fluid determined were protein (Lowry), total phospholipids (from phosphate after ashing) and the individual phospholipids (HPLC). During the spontaneous adsorption of the pulmonary surfactant the surface pressure increased from initially 26 mN/m to 44 mN/m in the equilibrium state. Simultaneously to the increase of the surface pressure, a continuous increase of the reflectivity signal was observed by quantitative Brewster angle microscopy (BAM). The film thickness is calculated from the reflectivity values using an optical model. The effect of the uncertainty of the refractive index, which has to be estimated, is discussed. The BAM images show the inhomogeneous nature of the surfactant film with three distinct phases of different reflectivity, even at relatively low surface pressures. For the brightest phase, the thickness amounts to approximately 12 nm in the equilibrium state of adsorption. This suggests a multilamellar structure. Additionally, we found visual evidence for an adsorption mechanism involving the spreading of vesicles at the interface, in agreement with published results. Differences in the morphology and thickness of the pulmonary surfactant film reported in the literature are obviously due to the varying experimental conditions and materials. We think that the experimental conditions chosen in our study provide a more realistic view of the structure in the lungs in vivo.

Assessment of cellular profile and lung function with repeated bronchoalveolar lavage in individual mice

In this study, we sought to develop procedures that would enable repeated bronchoalveolar lavage (BAL) in individual mice on multiple occasions. To achieve this objective, we first developed the procedures that would allow individual mice to survive a whole lung lavage, and then tested whether, on subsequent days, there was an effect of this initial BAL on the cell profile, lung permeability, and baseline respiratory function. Our results demonstrate that the repeated lavage procedure can be readily carried out in individual mice of different strains on multiple occasions. The lavage procedure itself results in immediate increases in respiratory system resistance and concomitant decreases in compliance, but these parameters return to prelavage values by the 2nd or 3rd day postlavage. Lavage also induces variable increases in inflammatory cells depending on the strain used. However, in all three strains examined here (A/J, BALB/c, and C3H/HeJ), inflammatory cell numbers returned to baseline values within 3 days after an initial lavage procedure. The ability to perform repeated BAL in individual mice should prove to be an extremely useful tool in a variety of functional genomic studies in the lung.

Modification of plasma proteins by cigarette smoke as measured by protein carbonyl formation

Exposure of human plasma to gas-phase (but not to whole) cigarette smoke (CS) produces oxidative damage to lipids [Frei, Forte, Ames & Cross (1991) Biochem. J. 277, 133-138], which is prevented by ascorbic acid. The ability of CS to induce protein damage was measured by the carbonyl assay and by loss of enzyme activity and protein -SH groups. Both whole and gas-phase CS caused formation of carbonyls in human plasma, which was partially inhibited by GSH but not by ascorbic acid or metal-ion-chelating agents. Isolated albumin exposed to CS showed much faster carbonyl formation (per unit protein) than did whole plasma; damage to isolated albumin was partially prevented by chelating agents. Isolated creatine kinase (CK) lost activity upon exposure to CS much faster than did CK in plasma. Direct addition to plasma of mixtures of some or all of the aldehydes reported to be present in CS caused protein carbonyl formation and inactivation of CK, but neither occurred to the extent produced by CS exposure.