The isolation of rat alveolar type II cells: a simplified approach using Percoll density centrifugation.

Colloidal silica-polyvinylpyrrolidinone solution (Percoll) is used in this study to purify type II alveolar pneumocytes obtained from elastase disaggregation of rat lung tissue. The crude lung cell suspension (containing 31.4±2.1% type II cells) was applied to a Percoll gradient established by centrifugation of phosphate-buffered saline with the Percoll. Color-coded density marker beads permitted the determination of the density of each resulting cellular layer. Harvesting of the type II cell-enriched layer yielded a cell population 92±2% pure for type II cells. Identification of type II cells was made using a modified Papanicolaou stain, a negative myeloperoxidase stain, negative leukocyte cell surface markers, and ultrastructural examination. Purification of crude rat lung cell suspensions with Percoll appears to be a rapid and inexpensive means of obtaining a replenishable type II cell population. [ABSTRACT FROM AUTHOR]