Abstract
Purpose :
To evaluate the impact of intraoperative dyes and internal limiting membrane (ILM) peeling on gene and protein expression of retinal glial cells.
Methods :
Expression of 6 genes and proteins related with retinal glia activation (vimentin, glial fibrillary acidic protein (GFAP), SERPINA-3, endothelin receptor type B (ERB), bone morphogenetic protein 7 (BNP7), secreted phosphoprotein-1 (osteopontin, SPP1)) was studied in four freshly enucleated (<24 hours) adult human eyes. Eyes initially underwent a simulated vitrectomy in vitro, and then 6-millimeter full thickness human retina pieces were trephined and treated with four different intraoperative dyes (IOD) (indocyanine green (ICG), brilliant blue G (BBG), trypan blue (TB) and triamcinolone) before peeling the ILM with an end-grasping forceps. Retinal tissue was then cultured in CO2-independent medium at 37 °C for 48 hours. At the end of the incubation period, retinal RNA and protein were extracted and quantified by qPCR and comparative densitometric analyses of the western blots, respectively. RNA and protein expressions were compared with three control groups, namely (1) untreated retina samples, (2) retina pieces treated with intraoperative dyes without peeling ILM and (3) retinal tissue where ILM was peeled without any dye.
Results :
ILM peeling without the use of any IOD significantly upregulated glial activation genes (GFAP 6.93±0.20, SERPINA-3 3.42±0.26, ERB 5.84±0.27, BNP7 5.62±0.20, SPP1 3.65±0.28 folds compared to controls). Use of IOD boosts up this response regardless of ILM peeling. ICG (vimentin 1.53±0.29, GFAP 10.27±1.08, SERPINA-3 59.99±6.00, ERB 2.26±0.29, BNP7 4.63±0.52, SPP1 2.80±0.15 folds) and BBG (GFAP 6.84±1.28, SERPINA-3 33.82±5.85, BNP7 1.34±0.23 folds) caused the most prominent gliotic response. These changes reflected themselves similarly in protein expression.
Conclusions :
Mechanical peeling of ILM induces retinal gliosis. Use of vitreoretinal dyes alone or in conjunction with ILM peeling potentiates the gliotic response.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.