Ultrastructural evidence of mucus in human conjunctival epithelial cultures.
OBJECTIVE
To demonstrate by ultrastructural techniques that human conjunctival epithelium cells in vitro can produce mucin-like secretion.


METHODS
Primary cultures of human conjunctival epithelial cells were grown in different culture media. Cultures were allowed to grow and were processed after 5 days and 1, 2, 3, 4, or 5 weeks for transmission and scanning electron microscopy, according to the method of Nichols et al. modified in our laboratory.


RESULTS
Marked differences were seen between primary cultures grown with or without hydrocortisone. A thick tannic acid-stained layer was observed when hydrocortisone was present in the culture medium; however, that layer was virtually absent in cultures grown with hydrocortisone-free media. Scanning electron microscopy revealed a dense deposit showing a network-like structure. Moreover, the age of the cultures clearly influenced the thickness of the tannic acid-stained deposit, which thickened as the cultures aged.


CONCLUSIONS
These results strongly suggest that the layer growing in the presence of hydrocortisone is mucus. The fact that this material became more abundant as the cultures aged indicates that mucus is actively produced and secreted by conjunctival epithelial cells in vitro. This study might contribute to the knowledge of mucus-deficient pathologies of the ocular surface.
University of Valladolid Institute of Ophthalmobiology (IOBA) Spain Valladolid,
Y C
YC
Diebold
M C
MC
Calonge
S C
SC
Callejo
M C
MC
Lázaro
R M
RM
Bringas
J M
JM
Herreras
D000818:Animals; D002417:Cattle / Q000097:blood / Q000196:embryology; D002478:Cells, Cultured; D003228:Conjunctiva / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D005312:Fetal Blood / Q000502:physiology; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009093:Mucus / Q000378:metabolism*
D006854:Hydrocortisone