Sequential bronchoalveolar lavages by endotracheal intubation in guineapigs

We examined the feasibility of performing repeated bronchoalveolar lavage (BAL) on guineapigs. We also determined the influence of lavage volume on cell recovery in these animals, verified if the free cell populations were altered by repeated lavage, and compared the results with those obtained after euthanasia. Live animals were intubated orotracheally by direct vision laryngoscopy and lavaged, except for the last BAL which was done on isolated lungs after euthanasia. Each animal was lavaged weekly for 8 weeks: weeks 1-5 lavages were done with 5 aliquots of 2 ml of normal saline, week 6 with 3 aliquots of 1 ml, week 7 with 3 aliquots of 2 ml, and week 8 with 5 aliquots of 2 ml after euthanasia. The first 5 BAL gave similar results in volumes recovered, total number of cells, cell viability and differentials. The total cell yield of lavages 6 and 7 was less than that of the first 5 BAL and BAL 8; cell differentials with these smaller lavages were similar except for the percentage of neutrophils which was slightly higher than with the 10 ml lavage at week 3. The final lavage gave similar results as the first 5 BAL in terms of total cells recovered, cell viability, and differentials. We conclude that repeated BAL is feasible in live guineapigs, and that it gives a similar cells yield as lung lavage obtained after euthanasia.