Decreased glutathione transferase levels in rd1/rd1 mouse retina: replenishment protects photoreceptors in retinal explants.
Currently much attention is focused on glutathione S transferase (GST)-induced suppression of apoptosis. The objective of our studies was therefore to see if GST isoenzymes rescue photoreceptors in retinal explants from rd1/rd1 mice, in which photoreceptors degenerate rapidly. Eyes from C3H rd1/rd1 and +/+ mice were collected at various time points between postnatal day (PN) 2 and PN28. Localization and content of alpha-GST and mu-GST was investigated by immunofluorescence and semi-quantitative Western blot analysis, respectively. In addition, PN2 and PN7 retinal explants were cultured till PN28, during which they were treated with 10 ng/ml alpha-GST or mu-GST. The spatiotemporal expression of both GST isoforms was closely similar: early presence in ganglion cell layer after which staining became restricted to Muller cells (particularly in the endfeet) and horizontal cell fibers in both rd1/rd1 and +/+. Doublets of alpha-GST and mu-GST were detected by Western blot analysis. Densitometry of these bands indicated steady reduction of alpha-GST content in rd1/rd1 retina starting from the second postnatal week. When alpha-GST and mu-GST were added exogenously to rd1/rd1 explants, photoreceptor rescue was produced that was more prominent in PN2 than in PN7 explants and more effective by alpha-GST than mu-GST. We propose that alpha-GST neuroprotection is mediated by reduction of tissue oxidative stress.
Ahuja
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Wallenberg Retina Centre, Department of Ophthalmology, Lund University, BMC-B13, Klinikgatan 26, Lund 221 84, Sweden.
Caffé
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Ahuja
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Ekström
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van Veen
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D000818:Animals; D015153:Blotting, Western; D005982:Glutathione Transferase / Q000378:metabolism*; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D009924:Organ Culture Techniques; D018384:Oxidative Stress / Q000502:physiology; D020419:Photoreceptor Cells, Vertebrate / Q000201:enzymology*; D012160:Retina / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development; D012162:Retinal Degeneration / Q000201:enzymology* / Q000235:genetics
D007527:Isoenzymes; D005982:Glutathione Transferase