Similar effects of selective laser trabeculoplasty and prostaglandin analogs on the permeability of cultured Schlemm canal cells.
OBJECTIVE
To evaluate whether selective laser trabeculoplasty and prostaglandin analogs regulate the permeability of cultured human Schlemm canal cells by inducing intercellular junction disassembly.


METHODS
Laboratory investigation.


METHODS
Intercellular junctions were made visible in living cells by making them fluoresce after transfection with a plasmid expressing the zonula occludens 1 protein tagged with green fluorescent protein. Schlemm canal cells were treated by direct laser irradiation; by exposure to media conditioned by either lasered Schlemm canal cells or trabecular meshwork cells; by exposure to the prostaglandin analogs latanoprost, bimatoprost, and travoprost; or by the addition of the nonprostaglandin agents brimonidine, timolol, and dorzolamide. Junction disassembly was monitored using fluorescence microscopy, and permeability alterations were measured as changes in conductivity using flow meters.


RESULTS
The direct laser irradiation of Schlemm canal cells caused a 3-fold increase in conductivity. Exposure of the cells to media conditioned by lasered Schlemm canal cells or trabecular meshwork cells induced junction disassembly and a 2- to 4-fold increase in conductivity. Exposure to prostaglandin analogs also induced junction disassembly and a 4- to 16-fold increase in conductivity, whereas the 3 nonprostaglandin agents tested were ineffective in both regards.


CONCLUSIONS
Exposure to factors secreted by lasered Schlemm canal cells and lasered trabecular meshwork cells and the application of prostaglandin analogs induced junction disassembly while increasing the permeability of Schlemm canal cells. These findings support our hypothesis that selective laser trabeculoplasty and prostaglandin analogs share a common mechanism that likely mediates their pressure-lowering effects.
Alvarado
Jorge A
JA
Beckman Vision Center, Department of Ophthalmology, University of California-San Francisco, 10 Koret Way, San Francisco, CA 94143-0730, USA. alvaradoj@vision.ucsf.edu
Iguchi
Rumiko
R
Martinez
Juan
J
Trivedi
Sheetal
S
Shifera
Amde Selassie
AS
D002463:Cell Membrane Permeability / Q000502:physiology*; D002478:Cells, Cultured; D003315:Cornea / Q000166:cytology* / Q000187:drug effects / Q000601:surgery; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007365:Intercellular Junctions / Q000502:physiology*; D053685:Laser Therapy; D053844:Lasers, Solid-State; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011461:Prostaglandins F, Synthetic / Q000494:pharmacology*; D012590:Sclera / Q000166:cytology* / Q000187:drug effects / Q000601:surgery; D014129:Trabecular Meshwork / Q000166:cytology* / Q000187:drug effects / Q000601:surgery; D014130:Trabeculectomy / Q000379:methods*; D014162:Transfection; D062826:Zonula Occludens-1 Protein
D008565:Membrane Proteins; D010750:Phosphoproteins; D011461:Prostaglandins F, Synthetic; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein; D049452:Green Fluorescent Proteins