Immunodetection of surfactant proteins in human organ of Corti, Eustachian tube and kidney.

The presence of surfactant proteins was investigated in the human organ of Corti, Eustachian tube and kidney tissues. It has previously been shown that lamellar bodies are present in hairy cells of organ of Corti, in the cytoplasm of secretory and lumen of tubal glands of Eustachian tube and kidney renal basement membrane. No evidence for the presence of surfactant proteins in the organ of Corti and kidney has been presented until now. The aim of this study was to find out if surfactant proteins were expressed in other epithelia such as organ of Corti, Eustachian tube and kidney. Surfactant proteins were identified using one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting. On one-dimensional Western blots, bands for surfactant protein A in human Eustachian tube (SP-A, 34 kDa) and in kidney extracts, and for surfactant protein D (SP-D, 43 kDa) in Eustachian tube and in kidney extracts (SP-D, 86 kDa), and for surfactant protein B (SP-B, 8 kDa) in human Eustachian tube and organ of Corti extracts were detected. Bands corresponded to monomeric forms of lung surfactant proteins. These results indicate the presence of SP-A and SP-D in kidney epithelium, SP-A, SP-B and SP-D in Eustachian tube and SP-B in the organ of Corti.