Abstract
Purpose:
To determine the effect of high dose advanced glycation end-products (AGEs) on neurite regeneration of isolated rat retinas, and also to determine the regenerative effects of different neurotrophic factors in AGE-exposed retinas.
Methods:
All of the procedures were performed in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. Retinal explants of 4 adult SD rats were three-dimensionally cultured in collagen gel and incubated in: 1) serum-free control culture media; 2) 100 μg/ml glucose-AGE-BSA, glycolaldehyde-AGE-BSA, glyceraldehyde-AGE-BSA media; 3 ) glucose-AGE, glycol-AGE, glycer-AGE+100 ng/ml neurotrophin 4 (NT-4) media; 4) glucose-AGE, glycol-AGE, glycer-AGE+100 ng/ml hepatocyte growth factor (HGF) media; 5) glucose-AGE, glycol-AGE, glycer-AGE+100ng/ml glial cell line derived neurotrophic factor (GDNF) media; and 6) glucose-AGE, glycol-AGE, glycer-AGE+100 ng/ml tauroursodeoxycholic acid (TUDCA) media. After 7 days, the number of regenerating neurites from the explants was counted under a phase-contrast microscope. Statistical analysis was performed by one-way ANOVA.
Results:
In retinas incubated with AGEs (glucose-AGE, glycol-AGE, and glycer-AGE), the numbers of regenerating neurites were significantly fewer than in retinas without AGE (7.16±4.38 vs 15.6±5.58, P=0.0046; 4.00±2.45 vs 15.6±5.58, P<0.0001; 4.69±4.70 vs 15.6±5.58, P=0.0003, respectively). All neurotrophic factors increased the number of neurites regenerating in AGEs-exposed retinas, but the most significant regenerative effect was detected in the NT4 group: 60.66±27.99 vs 7.16±4.38 (P<0.0001) in the NT4 group; 45.00±16.05 vs 7.16±4.38 (P<0.0001), in the HGF group; 23.75±5.56 vs 7.16±4.38 (P=0.0061) in the GDNF group; 39.6±9.07 vs 7.16±4.38 (P<0.0001) in the TUDCA group supplemented with glucose-AGE incubated retinas.
Conclusions:
NT-4 significantly enhances neurite regeneration in retinas exposed to high doses of AGE compared to other neurotrophic factors such as HGF, GDNF and TUDCA.
Keywords: 615 neuroprotection •
499 diabetic retinopathy •
694 retinal culture