Purchase this article with an account.
Marina G. Yefimova, Jean-Claude Jeanny, Xavier Guillonneau, Nicole Keller, Jeanine Nguyen–Legros, Claire Sergeant, Florian Guillou, Yves Courtois; Iron, Ferritin, Transferrin, and Transferrin Receptor in the Adult Rat Retina. Invest. Ophthalmol. Vis. Sci. 2000;41(8):2343-2351.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
purpose. The retina and other tissues need iron to survive. However, the normal
iron metabolism in rodent retinas had not been characterized. This
study was intended to investigate iron and iron homeostasis protein
(ferritin, transferrin [Tf] and transferrin receptor [Tf-R])
distribution in 20- to 55-day-old rat retinas.
methods. Iron was revealed on retinal sections directly by proton-induced x-ray
emission (PIXE) and indirectly by electron microscopy (EM). Ferritin,
Tf, and Tf-R proteins were localized by immunohistochemistry.
Transferrin expression was localized by in situ hybridization (ISH).
Transferrin and ferritin proteins and mRNA were analyzed by Western
blot analysis and reverse transcription–polymerase chain reaction
results. Iron is widely and unevenly distributed throughout the adult rat
retina. The highest concentration was observed by PIXE in the choroid
and the retinal pigmented epithelial cell (RPE) layer, and in inner
segments of photoreceptors (IS). Outer segments of photoreceptors (OS)
also contain iron. EM studies suggested the presence of iron inclusions
inside the photoreceptor discs. Choroid, RPE, and IS showed a strong
immunoreactivity for ferritin. Transferrin accumulated mainly in the IS
and OS areas and in RPE cells but can also be detected slightly in
retinal capillaries. Western blot analysis for Tf and ferritin
confirmed their presence in the adult neural retina. By RT–PCR, H- and
L-chains of ferritin and Tf mRNAs were expressed in neural retina, but
the main sites of Tf synthesis observed by ISH were the RPE and choroid
cell layers. Tf-R immunoreactivity was detected in the ganglion cell
layer, inner nuclear layer, outer plexiform layer, IS, RPE, and
choroid. These results were similar for all stages studied.
conclusions. For the first time, the present study characterized both iron and iron
homeostasis proteins in rodent retinas. In the outer retina, iron and
ferritin shared the same distribution patterns. In contrast, Tf, mainly
synthesized by RPE cells and detected in OS and IS areas, probably
helps to transport iron to photoreceptors through their Tf-R. This is a
likely pathway for filling iron needs in the outer
This PDF is available to Subscribers Only