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OPTIMIZATION OF REPEATED BRONCHOALVEOLAR LAVAGE IN RABBITS
Citation:
DYE, J. A., R. SLADE, J. E. RICHARDS, R. H. JASKOT, N. MANZO, AND G. TAYLOR. OPTIMIZATION OF REPEATED BRONCHOALVEOLAR LAVAGE IN RABBITS. Presented at 24th Annual Symposium of the Veterinary Comparative Respiratory Society, Jena, GERMANY, October 08 - 10, 2006.
Description:
Background. Bronchoalveolar lavage (BAL) is a relatively non-invasive technique used to obtain diagnostic samples from the lower airways of companion animals with respira¬tory disease. BAL is also commonly used in laboratory animals to assess pulmo¬nary changes after exposure to air pollutants. However, in experimental studies, BAL is typically performed as a terminal procedure, using large volumes of instillate (25-35 mL/ kg), thus allowing consistent (often > 70%) recovery, and quantitative assessment of BAL fluid cellular, microbiological culture, and biochemical indices. Study. Herein, we refined BAL in laboratory rabbits so that it could be used as a recoverable procedure, thus allowing repeated assessment of the same subject throughout a chronic air pollutant exposure study. In a cross-over manner, NZW rabbits (n=6; 2.7 - 3.2 kg) underwent BAL using either: (a) 5-mL aliquots of saline (LOW-VOL) pooled samples, or (b) a single 10 mL/kg saline (HIGH-VOL) sample. Results of the LOW- and HIGH-VOL procedures were compared to a terminal BAL procedure using 25 mL/kg. Rabbits were anesthetized with ketamine, midazolam and isoflurane, tran¬sorally intubated, and oxygenated for 5 minutes prior to and after BAL fluid collection. Animals were evaluated immediately post-BAL via pulse oximetry and end-tidal capnography. A pharyngeal swab and aliquots of BAL fluid from the first and final procedure were cultured for aerobic isolates. Serology for CAR Bacillus antibody was submitted. Results. All rabbits recovered uneventfully from either the LOW- or HIGH-VOL BAL procedures. Recovery time was more a function of the difficulty of intubation rather than the BAL volume instilled. No bacterial growth was isolated from BAL fluid samples while the swab grew Enterococcus faecalis. All serum samples were negative for CAR Bacillus anti¬body. The main disadvantage of the LOW-VOL method was that sample recovery was less predictable. On the other hand, although the HIGH-VOL method provided more consistent fluid recovery, certain biochemical indices fell below detectable limits due to greater dilution of epithelial lining fluid (ELF). Using serum and BAL fluid concentra¬tions of urea and albumin, estimates of ELF volume were compared for the three instillation volumes used. Conclusion. With appropriate pre- and post-lavage care, repeated recovery BAL is possible in rabbits.
(This abstract does not reflect US EPA policy).