Abstract
Purpose: :
The culture of lacrimal gland cells has proven to be difficult since acinar cells can only be maintained a short time under normal culture conditions. A Rotary Cell Culture System (RCCS) allows the creation of a microgravity environment of low shear force, high-mass transfer, and 3-dimensional cell culture of various cell types. Aim of this study was to evaluate the growth pattern and the secretory function of rabbit lacrimal gland acinar cells in a microgravity environment using a RCCS.
Methods: :
Lacrimal gland acinar cells from New Zealand White rabbits of both sexes were isolated and cultured in a RCCS up to 28 days. Cells were analysed by light and electron microscopy at day 7, 14, 21 and 28. Secretory function was tested by measuring the ß-hexosaminidase activity.
Results: :
After 7 days of culture, spheroidal aggregates with a mean diameter of 384.6 ± 111.8 µm (mean ± std. deviation) were found inside the RCCS. The spheroids consisted of acinar cell conglomerates, which showed organisation into acinus-like structures. During the culture period the mean diameter of the spheroids did not increase substantially. Necrotic centers inside the spheroids were noted at all time points. The diameter of the spheroids containing necrotic centers was significantly higher compared to spheroids without necrotic centers at day 14, 21 and 28 (p ≤ 0.05). The mean ratio of necrosis on the entire spheroid was 40 % on day 7, 38.9 % on day 14, 46.8 % on day 21 and 89.7 % on day 28. A significant increase of the necrosis ratio during the culture period was found (p ≤ 0.05). The evaluation of the secretory function showed a substantial response to stimulation with carbachol at day 7 and a diminished secretory response at day 14. On days 21 and 28, no considerable increase of ß-hexosaminidase release after stimulation with carbachol was found.
Conclusions: :
A simulated microgravity environment is capable to promote the development of three dimensional cell spheroids containing viable acinar cells up to 28 days with a substantial secretory response to carbachol up to 7 days and a diminished response up to 14 days. Due to the evolving central necrosis, it is unlikely that such simple three dimensional cell communities can serve as tissue equivalents for clinical transplantation, but they offer opportunities for further applications in basic and applied cell research on lacrimal gland cells.