Purpose: To investigate neuroprotective and axogenic properties of pigment epithelium-derived factor (PEDF) in retinal ganglion cells (RGC) in vitro and in vivo. Methods: Adult rat retinal cultures were treated with combinations of PBS and PEDF with or without a cell permeable analogue of cyclic adenosine monophosphate (cAMP), and RGC survival and neurite lengths quantified. The optic nerves of anesthetised rats were also crushed intraorbitally to transect all RGC axons followed by intravitreal injections of either PBS, PEDF or cAMP+PEDF every 7 days. RGC were back-filled with FluoroGold to quantify RGC survival and longitudinal optic nerve sections were stained with GAP43 antibodies to detect regenerating RGC axons. Results: An optimal dose of 2.5 × 10-5 μg/μl, promoted 65% more RGC survival than controls in vitro, increasing by 4.4- and 5-fold the number of RGC with neurites and the mean neurite length, respectively. Addition of cAMP with or without PEDF did not potentiate RGC survival or the mean number of RGC with neurites, but enhanced RGC neurite length by 1.4-fold, compared to PEDF alone. After ONC, PEDF protected RGC from apoptosis and increased the numbers of regenerating RGC axons in the optic nerve by 4.6- and 3.4-fold, respectively when compared to controls. cAMP did not enhance PEDF-induced RGC neuroprotection but potentiated its neuro-regenerative effects by 2-3-fold, increasing the number of RGC axons regenerating at 500 and 1000μm from the lesions site. Conclusions: This study is the first to demonstrate that PEDF enhances both RGC survival and axon regeneration in vitro and in vivo.
|Journal||Investigative Ophthalmology & Visual Science (IOVS)|
|Early online date||19 Mar 2013|
|Publication status||Published - Apr 2013|