Comparative evaluation of melanin content in melanosomes and melanolipofuscin granules from the human retinal pigment epithelium cells

Abstract

Purpose. Comparative study of the melanin content in melanosomes and melanolipofuscin granules from cells of the retinal pigment epithelium of the human eye. Material and methods. The research and comparison of melanosomes and melanolipofuscin granules from cells of human retinal pigment epithelium was carried out by the method of electron paramagnetic resonance (EPR) spectroscopy. Results. It was shown that the EPR spectra in both types of melanin granules, including the main parameters, were similar and corresponded to the EPR spectra characteristic of natural eumelanins and synthetic DOPA-melanin. Conclusion. The results of study indicate that in melanolipofuscin granules as well as in melanosomes, the pigment melanin (eumelanin) is contained, as evidenced by the similarity of their paramagnetic properties. Melanin content in melanosomes is higher than in melanolipofuscin granules on average of one and a half times, which follows from the concentration of their paramagnetic centers per granule.

Keywords

• retinal pigment epithelium
• melanin
• melanosomes
• melanolipofuscin granules
• lipofuscin
• electron paramagnetic resonance