Background: The secretion of the lacrimal gland provides 95% of the aqueous tears, which are essential for lubrication, nutrition and protection of the ocular surface. Long-term studies of acinar lacrimal gland cells in vitro are complicated by low proliferation rate and fast loss of cell function on plastic. Aim of this study was to evaluate the growth pattern and the secretory function of lacrimal gland acinar cells on amniotic membrane (AM) in a rabbit model.
Methods: Lacrimal gland acinar cells from Chinchilla Bastard and New Zealand White rabbits of both sexes were isolated and cultured on denuded amniotic membrane. Cells were analysed by light and electron microscopy. Secretory function was tested by measuring the beta-hexosaminidase activity.
Results: Three days after seeding to the amniotic membrane, the acinar cells had attached to each other and formed small cluster. Cell clusters consisted of 2-5 cell layers, and the cells showed fine granulation in their cytoplasm, typical for secreting cells. Between days 7 and 14 cell clusters increased in size, and acini-like structures with a central lumen were found. Cells showed polarity, with a basal nucleus and apical secretory granules. Between days 21 and 28 acini-like structures were still found inside the cell clusters. Accumulation of secretory material in the central lumen and desmosome formation connecting the apical cell structures was frequently evident. However, the number of cytoplasmatic granules decreased, and on parts of the AM, cell morphology changed to flat, spindle-shaped cells with a small nucleus. Stimulation with carbachol showed a strong beta-hexosaminidase release until day 7, with a decreasing secretory function detectable until day 21.
Conclusion: Acinar lacrimal gland cells can be successfully cultured on amniotic membrane up to 28 days, with a secretory response to carbachol up to 21 days. This model may be used for further experimental work, to elucidate cellular mechanisms in normal and diseased lacrimal tissue.