VISUALIZATION OF CONJUNCTIVAL GOBLET CELL ACTIN CYTOSKELETON AND MUCIN CONTENT IN TISSUE WHOLE MOUNTS

The purpose of the work was to visualize goblet cells, their cytoskele tons, and their content in tissue whole mounts of conjunctiva using co nfocal microscopy. Conjunctival tissue from rat, mouse, rabbit, and hu man were excised, fixed in 4% paraformaldehyde, and incubated either w ith rhodamine-labeled phalloidin to label filamentous actin or in comb ination with fluoresceinated lectins to label carbohydrates on goblet cell mucins. Tissues were evaluated by confocal microscopy. Phalloidin labeling of excised tissue facilitated visualization of goblet cells within the stratified epithelium of the conjunctiva. Phalloidin labele d the perimeter of the goblet cells, so that either in optical section or three-dimensional constructs of optical sections, the goblet cells appeared as plump empty clusters of cells in rat and mouse and as ind ividual plump empty cells in rabbit and human tissues. Double labeling of excised tissue with lectins demonstrated that the plump cells visu alized by labeling with phalloidin bound the label and were indeed gob let cells. At very high resolution one could see individual mucin pack ets within the goblet cells. Variation in intensity of lectin labeling of these mucin packets both between cells and within cells was eviden t. Streams of labeled mucin emanating from apical surfaces of goblet c ells could be visualized using the fluoresceinated lectins. The labeli ng of excised conjunctiva with fluorochrome-conjugated phalloidin allo ws visualization by confocal microscopy of goblet cells within the str atified epithelium. Double labeling with fluorochrome-conjugated lecti ns allows visualization of their content. These methods may be useful in studies of goblet cell differentiation, mucin content and secretion . (C) 1997 Academic Press Limited.