Age-dependent accumulation of lipofuscin in perivascular and subretinal microglia in experimental XXXX .

@entity1 @entity19 @entity9271 @entity989
Fundus autofluorescence (AF) imaging by confocal scanning laser ophthalmoscopy has been widely used by ophthalmologists in the diagnosis/monitoring of various @entity989 . It is believed that fundus AF is derived from lipofuscin in @entity989 ( @entity989 ) cells; however, direct clinicopathological correlation has not been possible in @entity1 . We examined fundus AF by confocal scanning laser ophthalmoscopy and confocal microscopy in normal C57BL/6 @entity19 of different ages. Increasingly strong AF signals were observed with age in the neuroretina and subretinal/ @entity989 layer by confocal scanning laser ophthalmoscopy. Unlike fundus AF detected in normal @entity1 subjects, @entity19 fundus AF appeared as discrete foci distributed throughout the retina. Most of the AF signals in the neuroretina were distributed around retinal vessels. Confocal microscopy of retinal and choroid/ @entity989 flat mounts demonstrated that most of the AF signals were derived from @entity9271 + perivascular and subretinal microglia. An age-dependent accumulation of @entity9271 + microglia at the subretinal space was observed. Lipofuscin granules were detected in large numbers in subretinal microglia by electron microscopy. The number of AF+ microglia and the amount of AF granules/cell increased with age. AF granules/lipofuscin were also observed in @entity989 cells in @entity19 older than 12 months, but the number of AF+ @entity989 cells was very low (1.48 mm(-2) and 5.02 mm(-2) for 12 and 24 months, respectively) compared to the number of AF+ microglial cells (20.63 mm(-2) and 76.36 mm(-2) for 6 and 24 months, respectively). The fluorescence emission fingerprints of AF granules in subretinal microglia were the same as those in @entity989 cells. Our observation suggests that perivascular and subretinal microglia are the main cells producing lipofuscin in normal aged @entity19 retina and are responsible for in vivo fundus AF. Microglia may play an important role in retinal aging and age-related @entity989 .
