title: Meibomian gland morphogenesis requires developmental eyelid closure and lid fusion.
abstract: Meibomian glands (MGs) play an important role in the maintenance of ocular surface health, but the mechanisms of their development are still poorly understood. The MGs arise from the epithelium at the junction of eyelid fusion, raising the possibility that defective eyelid fusion disturbs the formation of MGs.
  
  
  
  We examined, histologically and functionally, the development of MGs in mice with either normal or defective eyelid fusion, displaying eye-closed at birth (ECB) or eye-open at birth (EOB) phenotypes, respectively.
  
  
  
  The Meibomian anlage was detected in the epithelium at the eyelid fusion junction immediately after birth at postnatal day 0 (PD0), and it extended into the eyelid stroma at PD1 and started to branch and produce meibum at PD7 in the ECB mice. In contrast, few if any MG structures were detectable in the EOB mice in the early postnatal periods. The Meibomian gland ductile system was seen aligned along the eyelid margin in the adult ECB mice, but was absent or scarce in that of the EOB mice. While MG abnormalities were found in all EOB mice, the severity varied and corresponded to the position and the size of eye opening but not the genetic defects of the mice.
  
  
  
  Proper Meibomian gland formation and development require eyelid closure and fusion.
authors.affiliation: Department of Environmental Health, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0056, USA.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Ophthalmology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0056, USA.
authors.forename: Mindy
authors.initials: M
authors.lastname: Call
authors.affiliation: Department of Environmental Health, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0056, USA.
authors.forename: Maureen
authors.initials: M
authors.lastname: Mongan
authors.affiliation: Department of Ophthalmology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0056, USA.
authors.forename: Winston Whei-Yang
authors.initials: WW
authors.lastname: Kao
authors.affiliation: Department of Environmental Health, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0056, USA; Department of Ophthalmology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0056, USA. Electronic address: ying.xia@uc.edu.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xia
mesh_terms: D000818:Animals; D005141:Eyelid Diseases; D008537:Meibomian Glands; D051379:Mice; D009024:Morphogenesis
keywords: Embryonic eyelid closure; Eye-open at birth; Genetic mutant mice; Meibomian gland morphogenesis; Signaling pathway