Classification, location, and intensity of granules in retinal pigment epithelium following sodium iodate injection in rat animal model

Objective(s): Age-related macular degeneration (AMD) is one of the eye diseases that can affect a person’s central vision. Retinal pigment epithelium (RPE) cells are damaged in this medical condition and some pigments are presented in these cells. Here, we aimed to investigate melanin and lipofuscin granules of RPE cells as a precursor of AMD. Materials and Methods: Hooded rats (n=۱۸) were divided into two groups and received ۱۰۰ μl of sodium iodate (SI) into the retro-orbital sinus of their eyes at ۴۰ and ۶۰ mg/kg doses. The total number of melanin and lipofuscin granules, different types of granules, cytoplasmic dispersion of granules as well as morphological changes in the shape and number of nuclei of RPE cells were evaluated over the course of ۱-۳۰ days.Results: The total number of melanin pigments increases over time at a dose of ۴۰ mg/kg and decreases at a dose of ۶۰ mg/kg. Also, the total number of lipofuscin granules in ۴۰ mg/kg increases over time and decreases in ۶۰ mg/kg. Autofluorescent intensity (AF) is also increased at ۴۰ mg/kg, but at ۶۰ mg/kg, the highest intensity is on day ۷. Also, the highest number of multinucleated giant cells was on day ۷ at ۶۰ mg/kg and the most changes in cell appearance due to sodium iodate injection were seen on the first day after injection. Conclusion: We demonstrated that granules and autofluorescent intensity appear to decrease at high doses of sodium iodate, which is similar to the advanced stage of the AMD disease, where the number of granules and AF intensity increase in the middle and even early stages of the disease.

Keywords:

Age-related macular - degeneration , Fluorescent light intensity , Lipofuscin , Melanin , Sodium iodate