Abstract
Purpose: :
To determine whether brain-derived neurotrophic factor (BDNF), neurotrophin-4 (NT-4), vascular endothelial growth factor (VEGF)120, VEGF164 and citicoline inhibit neuronal cell death in isolated rat retinas exposed to a high glucose (HG) medium.
Methods: :
Six adult Sprague-Dawley rats were studied. After rats were killed, the retinas were isolated and cultured in serum-free medium. One group of explants was cultured in normal glucose (NG) medium and another group in HG medium. In addition, BDNF, NT-4, VEGF120, VEGF164 or citicoline were added to each type of media. After seven days in culture, retinas were fixed, cryosections prepared. To identify neuronal cells undergoing apoptosis, TdT-dUTP terminal nick-end labeling (TUNEL) staining were performed and co-stained with 4, 6-diamidino-2-phenyl-indole (DAPI). Semi-quantitative analysis of TUNEL positivity in the ganglion cell layer (GCL) was performed from the ratio of TUNEL-positive cells in relation to the total number of DAPI-stained nuclei. Statistical analysis was performed by Mann-Whitney U test.
Results: :
In retinas cultured in HG medium, TUNEL positivity in the GCL was significantly increased compared to those cultured in NG medium (40.7±7.7% vs. 28.1±11.9%; p=0.0011). In retinas incubated with BDNF, NT-4, VEGF120, VEGF164 or citicoline in HG media, TUNEL positivity in the GCL was significantly decreased compared to in HG media without BDNF, NT-4, VEGF120, VEGF164 or citicoline (27.6±10.8% vs. 40.7±7.7%; p=0.002, 22.5±11.1% vs. 40.7±7.7%; p=0.0003, 26.4±7.4% vs. 40.7±7.7%; p=0.0005, 31.5±9.2% vs. 40.7±7.7%; p=0.005, 31.7±8.7% vs. 40.7±7.7%; p=0.0024).
Conclusions: :
Retinas incubated in HG medium increase the number of apoptotic cell death in isolated adult rat retinas. BDNF, NT-4, VEGF120, VEGF164 and citicoline inhibit neuronal cell death in the retinas incubated in HG medium.
Keywords: diabetic retinopathy • apoptosis/cell death • neuroprotection