The localization of glutathione peroxidase in the photoreceptor cells and the retinal pigment epithelial cells of Wistar and Royal College of Surgeons dystrophic rats.
BACKGROUND
If degenerating photoreceptor outer segments not phagocytized by RPE cells in the retina of Royal College Surgeons (RCS) rats were to undergo peroxidation, the distribution of glutathione peroxidase (GSH-PO) in the mitochondria or cytoplasm of the retina might be altered. We evaluated the immunocytochemical localization of GSH-PO to identify subcellular organelles in sections of the retinas of RCS rats.


METHODS
Immunoblot analysis confirmed the presence of GSH-PO molecules in the retinas of RCS and Wistar rats aged 3 weeks. Sections were reacted with the F(ab) fragment of anti-rat alphaGSH-PO and then examined by laser scanning microscopy (LSM) and transmission electron microscopy (TEM).


RESULTS
The size of the GSH-PO molecule in the retina was about 21 KD in the mitochondria and 23 KD in the cytosol in both strains of rats. LSM revealed fluorescent granules in the photoreceptor inner segments of the Wistar rats, and immunohistochemical TEM revealed GSH-PO in the mitochondria of their photoreceptor inner segments and retinal pigment epithelial (RPE) cells. In the RCS rats, the degenerating photoreceptor outer segments were clearly seen to be positive for anti-GSH-PO by conventional light microscopy (CLM). However, the photoreceptor inner segments of the RCS rats were negative for staining with anti-GSH-PO by LSM, and no GSH-PO could be detected in the mitochondria of the photoreceptor inner segments or RPE cells by immuno-TEM.


CONCLUSIONS
Degeneration of the photoreceptor outer segments induced mitochondrial damage in the photoreceptor inner segments, and as a result GSH-PO shifted from the photoreceptor inner segments to the degenerating outer segments.
Akeo
K
K
Photon Medical Research Center, Hamamatsu University, School of Medicine, Shizuoka, Japan.
Tsukamoto
H
H
Okisaka
S
S
Hiramitsu
T
T
Watanabe
K
K
D000818:Animals; D004396:Coloring Agents; D005260:Female; D005979:Glutathione Peroxidase / Q000032:analysis*; D006735:Horseradish Peroxidase; D015151:Immunoblotting; D008751:Methylene Blue / Q000031:analogs & derivatives; D009993:Osmium Tetroxide; D010857:Pigment Epithelium of Eye / Q000201:enzymology* / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D012162:Retinal Degeneration / Q000201:enzymology*; D017948:Retinal Rod Photoreceptor Cells / Q000201:enzymology* / Q000648:ultrastructure; D004124:p-Dimethylaminoazobenzene
D004396:Coloring Agents; D004124:p-Dimethylaminoazobenzene; D006735:Horseradish Peroxidase; D005979:Glutathione Peroxidase; C028673:methylene green; D009993:Osmium Tetroxide; D008751:Methylene Blue