Abstract
Purpose: :
To investigate the biomechanical response of human optic nerve head astrocytes to compressive strain.
Methods: :
Primary human optic nerve head astrocytes were grown to confluence on pre-stretched, sylastic membranes (Flexcell® Bioflex® plates), using a custom built device. Media was changed twice weekly with DMEM/F12 media containing 10% FBS and 1% pen/strep. Upon reaching confluence the cells were serum deprived for 24 hours and subjected to 0%, 3%, or 12% cyclic compression at 1 Hz using the FlexerCell® Strain System FX-4000 for 2 or 24 hours. Western blots were carried out to identify GFAP, TGFβ-1, GM130, and ALDH1L1 expression regulation.
Results: :
Results for the Western blots show variable regulation for GFAP, TGFβ-1, GM130, and ALDH1L1. Following 2 hours of compression, an increase in protein expression was observed for all target proteins with increases of up to 1.6 fold. Protein expression increased further following 24 hours of compression.
Conclusions: :
This model is a novel and effective way to simulate the compressive strain predicted to be experienced by astrocytes of the lamina cribrosa under elevated IOP conditions in the human eye (Sigal et al, Experimental Eye Research, 2007). Results from the Western blots show significant regulation in protein expression following compressive strain and suggest activation of the astrocytes as early as 2 hours following 3% compression.
Keywords: astrocytes: optic nerve head • optic nerve • glia