Abstract
Purpose :
Lacrimal gland (LG) myoepithelial cells (MECs) surround the basolateral membranes of acinar cells. There is little information of the role of MECs in tear secretion. In this study, we investigated the relationship between LG acinar cells squeezing and myoepithelial contraction after cholinergic stimulation.
Methods :
Isolated lacrimal glands from 8 week-old male B6J mice were used for ex vivo two photon fluorescence imaging (Olympus FV1200MPE). To visualize the acinar cell surface shape, the LG were stained with Alexa Fluor® 555 conjugated wheat germ agglutinin (WGA). The LG was excited at 830 nm, and the fluorescence emission of WGA was detected at 570-650 nm. The LG was stimulated by acetylcholine (ACh) at different dosages ranging from 0.01 to 10 µM. The inhibitory effect of 2, 3-butanedione monoxime (BDM, 10mM), a myosin II ATPase inhibitor, on Ach-induced LG myoepithelial contraction was investigated. The fluorescence images were acquired at 25X magnification (approximately 1 flame/5sec) and the contraction was quantitatively analyzed by calculating the changing ratio of acinar area using ImageJ software.
Results :
The acinar cell squeezing was induced by ACh stimulation in a dose-dependent fashion. The changing ratio of acinar area were 10.4%, 26.3% (P=0.195), 112.7% (P=0.001), 94.9% (P=0.002), respectively at the dosage of 0.01µM, 0.1µM, 1µM, 10µM ACh. And the pre-treatment with BDM significantly, approximately 60%, suppressed the Ach-induced acinar cell squeezing.
Conclusions :
Our study demonstrated that LG acinar cells were squeezed by myoepithelial contraction following cholinergic stimulation. It suggested that myoepithelial contraction affects the tear secretion process.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.