Abstract
Abstract: :
Purpose: To develop a primary culture system that facilitates combined development of lacrimal ducts and acinar epithelial cells. Methods: Lacrimal glands from adult, female New Zealand white rabbits were collected and purified lacrimal parenchymal cells were isolated as previously reported (Guo et al., Exp. Eye Res. 71, 2000). Cell pellets were mixed with cold, neutralized, Type I collagen, and placed in culture dishes at 37ºC, which results in formation of a loose network of collagen fibrils. Cultures were maintained in HSM medium supplemented with FBS and EGF for 2-14 days. Additional cells were cultured in collagen (2-14 days), followed by the addition of Matrigel, and cultured for an additional 7-21 days. Results: As reported previously (Schechter et al., ARVO, 2000), Matrigel is highly effective for culturing histotypic lacrimal acinar epithelial cells, but does not promote formation of ducts. In contrast, lacrimal duct-like structures have been reported when lacrimal parenchymal cells were grown in a 3D collagen matrix (Nakamura et al., In Vitro Cell. Devel. Biol. 32, 1996). We observed arborous patterns of lacrimal ducts that were best developed after culturing 4-7 days in collagen. These were characterized (LM and EM) by tightly interdigitated epithelial cells, either lacking secretory granules or containing dense, round, granules histotypic of ducts in the in situ gland. Occasional small, oval, clumps of cells were evident at the terminations of ducts, suggesting rudimentary formation of acini. Cultures grown in collagen, followed by the addition of Matrigel, developed numerous ducts associated with large acinar-like clusters at their terminations. Acinar epithelial cells in the collagen/Matrigel cultures were essentially identical (LM and EM) to those in the in vivo gland. Conclusion: This modification of our previous method provides unique opportunities for future studies of the functional interactions between acinar and ductal epithelial cells.
Keywords: 452 lacrimal gland • 403 extracellular matrix • 472 microscopy: electron microscopy