ABSTRACT. The aim of this study was to determine the developmental changes of small leucine-rich proteoglycans (PGs), decorin, biglycan and fibromodulin, in ICR mouse retinas and to elucidate their role in the adult retina using kainic acid (KA)-induced retinal degeneration model. Retinas of prenatal, postnatal and adult mice were collected for histological and immunohistochemical staining to investigate the changes in distribution of these PGs. Decorin-and fibromodulin-immunostainings were diffusely distributed at prenatal and early postnatal stages and were stronger in the adult retina. However, biglycan was moderately distributed in the prenatal and early postnatal stages and was faint in the adult retina. Retinas were collected at 1, 3 and 7 days after intravitreal injection of KA. Retinas of KA injected eyes underwent shrinkage accompanied by serious damage in the inner layers. Decorin and fibromodulin were upregulated in the inner retinal layers of KA-injected eyes compared to the normal ones. Our results suggest that decorin and fibromodulin play key roles in retinal differentiation, and contribute to the retinal damage and repair process. However, biglycan may have no or only a limited role in the mouse retinal development or repair process.KEY WORDS: biglycan, decorin, fibromodulin, kainic acid, retinal development and damage.

ABSTRACT. The aim of the present study was to determine the distribution of chondroitin sulfate proteoglycans in the mouse retina and optic nerve of the prenatal and postnatal mouse by immunohistochemistry. At embryonic day (E) 18, chondroitin-4-sulfate (C4S), chondroitin-6-sulfate (C6S) and biglycan were detected in the retina and optic nerve. However, aggrecan was seen in the retina but not in the optic nerve. At postnatal day (P) 7, aggrecan and biglycan were clearly observed in the optic nerve, inner nuclear layer and ganglion cell layer and diffuse in the outer retina. C4S diffusely distributed in the retina and optic nerve, but C6S was mainly confined to the photoreceptor layer and optic nerve sheath. At P42, biglycan showed diffuse distribution in the retina and optic nerve with intense staining in nerve-fiber rich layers. Aggrecan showed weak staining at the inner plexiform layer with higher density in the outer and inner nuclear layers, outer plexiform layer and ganglion cell layer. Both C4S and C6S were detected in the optic nerve and retina, but C6S showed strong immunostaining in the photoreceptor layer. The distributions of these proteoglycans with respect of time course during development of the retina and optic nerve suggest that they may have unique or overlapping roles in development and maintenance of the retina and optic nerve.KEY WORDS: chondroitin sulfate proteoglycan, development, optic nerve, retina, spatiotemporal distribution.