Expression of extracellular matrix components in the meibomian gland

PurposeExtracellular matrix (ECM) is a key component of the stem cell local microenvironment. Our study aims to explore the periglandular distribution of major components of ECM in the Meibomian gland (MG). MethodsHuman eyelids and mouse eyelids were collected and processed for immunofluorescence staining. ResultsHuman MG tissues stained positive for collagen IV alpha 1, collagen IV alpha 2, collagen IV alpha 5, and collagen IV alpha 6 around the acini and duct, but negative for collagen IV alpha 3 and collagen IV alpha 4. The mouse MG were stained positive for the same collagen IV subunits as early as postnatal day 15. Laminin alpha 2, laminin beta 1 and perlecan stained the regions surrounding the acini and the acinar/ductal junction in the human MG, but not the region around the duct. Tenascin-C was found specifically located at the junctions between the acini and the central ducts. Neither agrin nor endostatin was found in the human MG tissues. ConclusionThe ECM expresses specific components in different regions around the MG, which may play a role in MG stem cell regulation, renewal, and regeneration.