Abstract
Abstract: :
Purpose: Selenium is known to occur in the enzyme, glutathione peroxidase, and plays an important role as an antioxidant. The objective of this investigation was to determine if amounts of selenium are selectively accumulated in different regions of the retina or uniformly distributed with eccentricity. Methods: Nine human retinas were analyzed for selenium. Five of these were sectioned into a disc and two concentric annuli centered on the fovea using trephines having diameters of 3, 11, and 21 mm. The sections had areas of 7.1, 93, and 343 mm2, respectively. Corresponding sections of these retinas were combined and analyzed together. For two donors, the whole retina of one eye was analyzed for selenium and the other retina was sectioned for analysis as described above. Selenium was determined using Atomic Fluorescence Spectroscopy after digestion of the retinal tissues in nitric acid. Results: The two whole retinas were found to have an average of 0.370.22 nmole/retina of selenium as compared to the companion retinas which had 0.300.12 nmole/retina as determined from the sum of the selenium amounts measured in the individual sections. The inner, medial, and outer portions of these two sectioned retinas were found to contain an average of 2.11.0, 1.10.4, and 0.60.2 pmole/mm2, respectively. The five retinas that were sectioned and pooled for analysis were found to have average amounts of 3.8, 1.3, and 0.6 pmole/mm2 respectively in the same three sections. Conclusions: This limited data set indicates that selenium is not uniformly distributed within the human retina but rather concentrated to a greater extent within the macula. If confirmed, these data would support the hypothesis that selenium may be an important antioxidant involved in protection of the macula from radical oxidants.
Keywords: 554 retina • 321 antioxidants • 460 macula/fovea