Abstract
Abstract: :
Purpose: Recent studies demonstrated that short peptides derived from activity-dependent neuroprotective protein are neuroprotective at femtomolar concentrations. We evaluated these findings in cultures of purified retinal ganglion cells (RGC) using two such peptides, ADNF-9 and NAP. In a second step we investigated the influence on neurite outgrowth and regeneration in retinal explants. Methods: RGCs were purified from newborn (P0 - P2) rat retina by immunopanning with antibodies against Thy1.1 and cultured in serumfree N2 medium for 2 days. RGCs were treated with ADNF-9 and NAP at concentrations ranging from 10e-18 to 10e-10 M. Survival was quantified by counting viable cells under phase-contrast microscopy and normalizing to controls. Retinal explants from postnatal (P9 - P11) rats were cultured in three-dimensional fibrin clots in serumfree medium for 3 days. Explants were treated with NAP (1µM) and ADNF-9 (1 µM). Neurite outgrowth was visualized by staining with sudan black and quantified by measuring axonal length. Results: Both peptides enhanced survival of RGCs in a dose-dependent manner. ADNF-9 showed a maximal effect at 10e-13 M with an increase of survival to 177%, CI95 [149, 204]. NAP showed a maximal effect at 5e-12 M with an increase of survival to 167%, CI95 [146,189]. In the explants, 1 µM ADNF-9 enhanced axonal outgrowth to 124%, CI95 [116, 133] and 1 µM NAP to 114%, CI95 [94, 135]. Conclusions: Both peptides, ADNF-9 and NAP, do not only increase neuronal cell survival in culture but also support regeneration and neurite outgrowth in retinal explants. These peptides deserve further attention as potential neuroprotective compounds.
Keywords: neuropeptides • neuroprotection • ganglion cells