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Abstract #48260 Published in IGR 13-4
Neuroprotective effects of tempol acyl esters against retinal ganglion cell death in a rat partial optic nerve crush model
Thaler S; Fiedorowicz M; Grieb P; Wypych Z; Knap N; Borowik T; Zawada K; Kaminski J; Wozniak M; Rejdak RActa Ophthalmologica 2011; 89: 555-560
PURPOSE: The aim of this study is to search for more effective derivatives of the superoxide dismutase mimetic tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl). Although tempol is neuroprotective in a rat partial optic nerve crush (PONC) model, relatively high doses are required to exert this effect. METHODS: Tempol acyl esters with different-length fatty acids (tempol-C4, tempol-C8, tempol-C12 and tempol-C16) were synthesized and the following properties were evaluated: water-octanol partition coefficient, liposome-liposome energy transfer, and electron paramagnetic resonance (EPR). Brown Norway rats underwent PONC and received tempol or acyl esters intraperitoneally once daily for 7 consecutive days. We then compared the effects of tempol and its four esters on retinal ganglion cell (RGC) damage using a retrograde labelling method. RESULTS: The water-octanol partition coefficient increased with increasing length of attached acyl chain. However, the energy of the liposome-liposome transfer seemed to be optimal for tempol-C8 and tempol-C12. The EPR signal was very similar for all tested compounds, suggesting similar efficiency of superoxide scavenging. Partial optic nerve crush in vehicle-treated animals reduced RGC numbers by approx. 59% when compared with sham-operated eyes. Tempol did not affect RGC loss at a dose of 1 mg/kg. In contrast, at molar doses equivalent to 1 mg/kg of tempol, tempol-C8 showed a significant neuroprotective effect, whereas tempol-C4, tempol-C12 and tempol-C16 did not act neuroprotectively. CONCLUSION: Manipulating the hydrophobicity of tempol seems to be a promising tool for developing more potent neuroprotectants in the PONC degeneration model. However, the resulting compounds need further pharmacological evaluation.
Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany. sebastian.thaler@uni-tuebingen.de
Classification:
11.8 Neuroprotection (Part of: 11 Medical treatment)
5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
11.14 Investigational drugs; pharmacological experiments (Part of: 11 Medical treatment)
