Der protektive Einfluss Müllerʼscher Gliazellen auf retinale Ganglienzellen

Zusammenfassung

Einleitung Die Müllerʼschen Gliazellen übernehmen in der Netzhaut vielfältige Aufgaben und gewährleisten damit deren regelrechte Funktion. Wie stark die neuroprotektive Wirkung von Müller-Zellen auf retinale Ganglienzellen (RGC) ist, soll untersucht werden.

Material und Methoden RGC wurden für 24 Stunden alleine oder in Kokultur mit Müllerʼschen Gliazellen unter normoxischen (20% O₂, 5% CO₂) und hypoxischen (0,2% O₂, 5% CO₂, 94,8% N₂) Bedingungen kultiviert. Die Anzahl lebender RGC und die Länge der neu ausgebildeten Neuriten dienten zur Beurteilung der Zellvitalität.

Ergebnisse Unter normoxischen Kulturbedingungen war die Anzahl vitaler RGC in Kokultur (62,85 ± 2,06%) signifikant höher (p < 0,01) als in der homotypischen RGC-Kultur (47,29 ± 2,83%). Unter Hypoxie war die Anzahl vitaler RGC in der Kokultur (41,07 ± 2,28%) ebenfalls signifikant höher (p < 0,01) als in der homotypischen RGC-Kultur (28,49 ± 2,16%). Die Länge der neu gebildeten Neuriten war in der normoxischen Kokultur am größten (90,7 ± 7,4 µm), zeigte aber nur im Vergleich zwischen normoxischer Kokultur und homotypischer RGC-Kultur einen signifikanten Unterschied (p = 0,04).

Schlussfolgerung Müllerʼsche Gliazellen unterstützen das Überleben von RGC unter normoxischen und hypoxischen Bedingungen. Ein weiterer Parameter zur Bewertung der Zellvitalität neben der Anzahl lebender RGC ist die Länge der neu ausgebildeten Neuriten.

Abstract

Introduction Müller glial cells carry out different tasks to warrant normal retinal functions. The aim of this study was to investigate if Müller cells also support retinal ganglion cells (RGC).

Materials and Methods RGC were cultured for 24 hours in the presence or absence of Müller glial cells under normoxic (20% O₂, 5% CO₂) or hypoxic (0.2% O₂, 5% CO₂, 94.8% N₂) culture conditions. The number of vital RGC and the length of the newly developed neurites were evaluated.

Results Under normoxic conditions, RGC vitality was significantly higher (p < 0.01) when cultured with Müller cells (62.85 ± 2.06%) than without (47.29 ± 2.83%). Under hypoxia, RGC vitality was significantly higher (p < 0.01) in co-cultures (41.07 ± 2.28%) than in homotypic RGC cultures (28.49 ± 2.16%). The maximum length of the newly developed neurites was found in the normoxic co-culture (90.7 ± 7.4 µm), but showed only a minor difference (p = 0.04) when compared to the normoxic homotypic RGC culture.

Conclusion Müller glial cells support RGC under normoxic and hypoxic culture conditions. Length of newly developed neurites and number of surviving RGC are both parameters to evaluate cell vitality.

Schlüsselwörter

Retina - Neurodegeneration - Glaukom - Müller-Zellen - Ganglienzellen

Key words

retina - neurodegeneration - glaucoma - Müller cells - ganglion cells

• Literatur

• 1 Flammer J, Mozaffarieh M. What is the present pathogenetic concept of glaucomatous optic neuropathy?. Surv Ophthalmol 2007; 52 (Suppl. 02) S162-S173
• 2 Lee DA, Higginbotham EJ. Glaucoma and its treatment: a review. Am J Health Syst Pharm 2005; 62: 691-699
• 3 Quigley HA. Recognizing structural damage to the optic nerve head and nerve fiber layer in glaucoma. Am J Ophthalmol 1998; 125: 563 author reply 564–565
• 4 Nickells RW. Apoptosis of retinal ganglion cells in glaucoma: an update of the molecular pathways involved in cell death. Surv Ophthalmol 1999; 43 (Suppl. 01) S151-S161
• 5 Heijl A, Leske MC, Bengtsson B. et al. Reduction of intraocular pressure and glaucoma progression: results from the Early Manifest Glaucoma Trial. Arch Ophthalmol 2002; 120: 1268-1279
• 6 Leske MC, Heijl A, Hussein M. et al. Factors for glaucoma progression and the effect of treatment: the early manifest glaucoma trial. Arch Ophthalmol 2003; 121: 48-56
• 7 Sucher NJ, Lipton SA, Dreyer EB. Molecular basis of glutamate toxicity in retinal ganglion cells. Vision Res 1997; 37: 3483-3493
• 8 Quigley HA. Neuronal death in glaucoma. Prog Retin Eye Res 1999; 18: 39-57
• 9 Tezel G, Wax MB. Increased production of tumor necrosis factor-alpha by glial cells exposed to simulated ischemia or elevated hydrostatic pressure induces apoptosis in cocultured retinal ganglion cells. J Neurosci 2000; 20: 8693-8700
• 10 Hernandez MR. The optic nerve head in glaucoma: role of astrocytes in tissue remodeling. Prog Retin Eye Res 2000; 19: 297-321
• 11 Kawasaki A, Otori Y, Barnstable CJ. Müller cell protection of rat retinal ganglion cells from glutamate and nitric oxide neurotoxicity. Invest Ophthalmol Vis Sci 2000; 41: 3444-3450
• 12 Unterlauft JD, Eichler W, Kuhne K. et al. Pigment epithelium-derived factor released by Muller glial cells exerts neuroprotective effects on retinal ganglion cells. Neurochem Res 2012; 37: 1524-1533
• 13 Unterlauft JD, Claudepierre T, Schmidt M. et al. Enhanced survival of retinal ganglion cells is mediated by Muller glial cell-derived PEDF. Exp Eye Res 2014; 127: 206-214
• 14 Bringmann A, Pannicke T, Grosche J. et al. Müller cells in the healthy and diseased retina. Prog Retin Eye Res 2006; 25: 397-424
• 15 Stone J, Itin A, Alon T. et al. Development of retinal vasculature is mediated by hypoxia-induced vascular endothelial growth factor (VEGF) expression by neuroglia. J Neurosci 1995; 15: 4738-4747
• 16 Walsh N, Valter K, Stone J. Cellular and subcellular patterns of expression of bFGF and CNTF in the normal and light stressed adult rat retina. Exp Eye Res 2001; 72: 495-501
• 17 Harada T, Harada C, Kohsaka S. et al. Microglia-Müller glia cell interactions control neurotrophic factor production during light-induced retinal degeneration. J Neurosci 2002; 22: 9228-9236
• 18 Eichler W, Yafai Y, Keller T. et al. PEDF derived from glial Müller cells: a possible regulator of retinal angiogenesis. Exp Cell Res 2004; 299: 68-78
• 19 Seki M, Tanaka T, Sakai Y. et al. Müller Cells as a source of brain-derived neurotrophic factor in the retina: noradrenaline upregulates brain-derived neurotrophic factor levels in cultured rat Müller cells. Neurochem Res 2005; 30: 1163-1170
• 20 Wen R, Tao W, Li Y. et al. CNTF and retina. Prog Retin Eye Res 2012; 31: 136-151
• 21 Fischer D, Leibinger M. Promoting optic nerve regeneration. Prog Retin Eye Res 2012; 31: 688-701
• 22 Mey J, Thanos S. Intravitreal injections of neurotrophic factors support the survival of axotomized retinal ganglion cells in adult rats in vivo. Brain Res 1993; 602: 304-317
• 23 Fischer D, Pavlidis M, Thanos S. Cataractogenic lens injury prevents traumatic ganglion cell death and promotes axonal regeneration both in vivo and in culture. Invest Ophthalmol Vis Sci 2000; 41: 3943-3954
• 24 Lorber B, Berry M, Logan A. Different factors promote axonal regeneration of adult rat retinal ganglion cells after lens injury and intravitreal peripheral nerve grafting. J Neurosci Res 2008; 86: 894-903
• 25 Müller A, Hauk TG, Fischer D. Astrocyte-derived CNTF switches mature RGCs to a regenerative state following inflammatory stimulation. Brain 2007; 130: 3308-3320
• 26 Lorber B, Berry M, Douglas MR. et al. Activated retinal glia promote neurite outgrowth of retinal ganglion cells via apolipoprotein E. J Neurosci Res 2009; 87: 2645-2652
• 27 Müller A, Hauk TG, Leibinger M. et al. Exogenous CNTF stimulates axon regeneration of retinal ganglion cells partially via endogenous CNTF. Mol Cell Neurosci 2009; 41: 233-246
• 28 Lorber B, Berry M, Logan A. et al. Effect of lens lesion on neurite outgrowth of retinal ganglion cells in vitro. Mol Cell Neurosci 2002; 21: 301-311
• 29 Lange J, Yafai Y, Reichenbach A. et al. Regulation of pigment epithelium-derived factor production and release by retinal glial (Müller) cells under hypoxia. Invest Ophthalmol Vis Sci 2008; 49: 5161-5167