کد مقاله کد نشریه سال انتشار مقاله انگلیسی ترجمه فارسی نسخه تمام متن
8267700 1534946 2016 23 صفحه PDF سفارش دهید دانلود رایگان
عنوان انگلیسی مقاله ISI
Photoaging of retinal pigment epithelial melanosomes: The effect of photobleaching on morphology and reactivity of the pigment granules
ترجمه فارسی عنوان
عکسبرداری از ملانوزومهای اپیتلیال رنگدانه شبکیه: اثر پیوند بر روی مورفولوژی و واکنشی گرانولهای رنگدانه
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موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی سالمندی
چکیده انگلیسی
To elucidate the mechanism of age-related changes in antioxidant and photoprotective properties of human retinal pigment epithelium (RPE) melanosomes, the effect of in vitro photoaging of bovine RPE melanosomes was examined employing an array of complementary spectroscopic and analytical methods. Electron paramagnetic resonance (EPR) spectroscopy, saturation recovery EPR, atomic force microscopy (AFM) and dynamic light scattering (DLS) were used to determine melanin content of control and photobleached melanosomes, and to monitor changes in their morphology. Methylene blue (MB), TEMPO choline, dysprosium(III) ions and singlet oxygen were employed as molecular probes to characterize the efficiency of control and photobleached melanosomes to interact with different reagents. EPR oximetry, UV-vis absorption spectroscopy, iodometric assay of lipid hydroperoxides and time-resolved singlet oxygen phosphorescence were used to analyze the efficiency of photobleached and untreated melanosomes to inhibit MB-photosensitized oxidation of liposomal lipids. The obtained results revealed that, compared to untreated melanosomes, moderately photobleached melanosomes protected unsaturated lipids less efficiently against photosensitized peroxidiation, while weakly photobleached melanosomes were actually better antioxidant and photoprotective agents. The observed changes could be attributed to two effects - modification of the melanosome morphology and oxidative degradation of the melanin functional groups induced by different degree of photobleaching. While the former increases the accessibility of melanin nanoaggregates to reagents, the latter reduces the efficiency of melanin to interact with chemical and physical agents.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Free Radical Biology and Medicine - Volume 97, August 2016, Pages 320-329
نویسندگان
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