Abstract
Purpose: :
In previous studies, we reported that murine lacrimal gland is capable of repair following experimentally induced injury. We also reported that the number of stem/progenitor cells was increased during the repair phase (2-3 days following injury) and that these cells were actively proliferating during that phase. The aim of the present study was to determine if stem/progenitor cells can be isolated from the lacrimal gland and propagated in vitro.
Methods: :
Lacrimal gland injury was induced by injection of recombinant human interleukin-1 (IL-1) whereas injection of saline (vehicle for IL-1) served as control. Two and half days following injection, the lacrimal glands were removed and used to prepare explants or acinar cells for tissue culture. One piece of the lacrimal gland was processed for histopathology and immunohistochemistry. Cells derived from the explants and the acinar cells were grown in DMEM supplemented with 10% fetal bovine serum. Cells were stained for the stem cell marker, nestin, and proliferation was measured using an antibody against Ki67. The adipogenic and osteogenic capabilities of these cells was also tested in vitro.
Results: :
Our results show that nestin-positive cells can be easily isolated from IL-1 injected, but not saline injected lacrimal glands. The cells also stained positive for another intermediate filament protein, vimentin, and some were also positive for alpha-smooth muscle actin. Lacrimal gland mesenchymal stem cells proliferate in vitro and can be induced to form adipocytes or osteoblasts attesting for their mesenchymal stem cell property. When these cells were grown in collagen scaffolds, they formed acinar- and ductal-like structures.
Conclusions: :
We conclude that murine lacrimal glands contain mesenchymal stem cells that participate in tissue repair. These cells can be easily isolated and propagated in vitro. Future studies will test the effect of other scaffolds and growth factors/cytokines known to regulate lacrimal gland functions.
Keywords: lacrimal gland • cornea: tears/tear film/dry eye • inflammation