Skip Header

You are using a version of browser that may not display all the features of this website. Please consider upgrading your browser.

Distribution of surfactant proteins in type II pneumocytes of newborn, 14-day old, and adult rats: an immunoelectron microscopic and stereological study.

Schmiedl A., Ochs M., Muhlfeld C., Johnen G., Brasch F.

Surfactant proteins (SP) have an important impact on the function of the pulmonary surfactant. In contrast to humans, rat lungs are immature at birth. Alveolarization starts on postnatal day 4. Little is known about the distribution of SP during postnatal alveolarization. By immunoelectron microscopy, we studied the distribution of SP-A, SP-D, SP-B, and precursors of SP-C in type II pneumocytes before, near the end and after alveolarization and in mature lungs. We determined the subcellular volume fractions and the relative labeling index to obtain information about preferential labeling of compartments and non-randomness of labeling. Independently of alveolarization, the overall cellular distribution of SP was non-random. A preferential labeling for SP-A and SP-D was found in small vesicles and multivesicular bodies (mvb). SP-B and precursors of SP-C were localized in mvb and lamellar bodies (lb). There are no postnatal changes in labeling for all three SP in these compartments. Labeling intensity for SP-B in lb increased in close correlation with a significant increase in the volume fractions of lb during alveolarization. Our results support the concept that postnatal alveolarization in rat lungs is associated with significant increases in the SP-B content in lb and volume fraction of lb in type II pneumocytes. The postnatal compartment-specific distribution of SP-A, precursors of SP-C and SP-D does not change.

Histochem. Cell Biol. 124:465-476(2005) [PubMed] [Europe PMC]

UniProt is an ELIXIR core data resource
Main funding by: National Institutes of Health

We'd like to inform you that we have updated our Privacy Notice to comply with Europe’s new General Data Protection Regulation (GDPR) that applies since 25 May 2018.

Do not show this banner again