PURPOSE: To visualize the in vivo structure and to investigate the composition of rat precorneal tear film. METHODS: An in vivo cryofixation with freeze substitution method of electron microscopy was used for the study. For light and transmission electron microscopy, a small amount of aluminum powder was used as a tracer spread on the corneal surface. The eyeballs were immediately and quickly frozen by pouring an isopentane-propane mixture cooled by liquid nitrogen directly over the eyes. For scanning electron microscopy, the corneal surface was freeze-fractured after the cryofixation. The specimens were then freeze-substituted and prepared conventionally for microscopic observation. RESULTS: The tear film appeared as a layer of homogeneous and fine network-like structures varying from 2 to 6 microns in thickness on the corneal surface, with a membrane-like layer covering its surface. The aluminum powder was located on the surface of the tear film. The tear film could be removed completely by applying 10% or 20% acetylcysteine, but not by phosphate buffer. CONCLUSIONS: The in vivo structure of the rat tear film is composed primarily of mucus, with a lipid layer covering its surface but without a free aqueous layer. The "three layers theory" of tear film structure requires revisions.
PURPOSE: To visualize the in vivo structure and to investigate the composition of rat precorneal tear film. METHODS: An in vivo cryofixation with freeze substitution method of electron microscopy was used for the study. For light and transmission electron microscopy, a small amount of aluminum powder was used as a tracer spread on the corneal surface. The eyeballs were immediately and quickly frozen by pouring an isopentane-propane mixture cooled by liquid nitrogen directly over the eyes. For scanning electron microscopy, the corneal surface was freeze-fractured after the cryofixation. The specimens were then freeze-substituted and prepared conventionally for microscopic observation. RESULTS: The tear film appeared as a layer of homogeneous and fine network-like structures varying from 2 to 6 microns in thickness on the corneal surface, with a membrane-like layer covering its surface. The aluminum powder was located on the surface of the tear film. The tear film could be removed completely by applying 10% or 20% acetylcysteine, but not by phosphate buffer. CONCLUSIONS: The in vivo structure of the rat tear film is composed primarily of mucus, with a lipid layer covering its surface but without a free aqueous layer. The "three layers theory" of tear film structure requires revisions.
Authors: Niko L Setälä; Juha M Holopainen; Jari Metso; Gebrenegus Yohannes; Jaakko Hiidenhovi; Leif C Andersson; Ove Eriksson; Alexandra Robciuc; Matti Jauhiainen Journal: J Lipid Res Date: 2010-08-19 Impact factor: 5.922
Authors: Jinxin Huang; Kye-sung Lee; Eric Clarkson; Matthew Kupinski; Kara L Maki; David S Ross; James V Aquavella; Jannick P Rolland Journal: Opt Lett Date: 2013-05-15 Impact factor: 3.776
Authors: Jinxin Huang; Eric Clarkson; Matthew Kupinski; Kye-Sung Lee; Kara L Maki; David S Ross; James V Aquavella; Jannick P Rolland Journal: Biomed Opt Express Date: 2013-08-29 Impact factor: 3.732