Environmental light enhances survival and axonal regeneration of axotomized retinal ganglion cells in adult cats.
A segment of peripheral nerve was transplanted to the cut stump of the optic nerve to facilitate axonal regeneration of retinal ganglion cells (RGCs) in adult cats. The cats were reared under different light environment: 12 h light-12 h darkness, additional flash light under conventional light cycle, or 24 h darkness. After 60 days, the density and morphology of RGCs with regenerated axons were examined with retrograde labeling by fluoro-ruby and intracellular injections of Lucifer Yellow. In the retina of cats reared in darkness, densities of RGCs with regenerated axons were 11-42% of those in the retina of cats reared under conventional light and dark cycle. More than half of the labeled RGCs were degenerative in the retina of cats reared in darkness, while most RGCs were normal under conventional environment or flash light. We conclude that environmental light is essential for the survival and axonal regeneration of axotomized RGCs.
Watanabe
M
M
Department of Physiology, Institute for Developmental Research, Aichi, Japan.
Inukai
N
N
Fukuda
Y
Y
D000818:Animals; D001370:Axonal Transport; D001369:Axons / Q000502:physiology / Q000528:radiation effects; D019771:Axotomy; D002415:Cats; D002470:Cell Survival / Q000528:radiation effects; D003624:Darkness; D003911:Dextrans; D005260:Female; D005456:Fluorescent Dyes; D005786:Gene Expression Regulation / Q000528:radiation effects; D016762:Genes, fos / Q000528:radiation effects; D006133:Growth Substances / Q000096:biosynthesis / Q000235:genetics; D007546:Isoquinolines; D008027:Light; D008029:Lighting; D008297:Male; D009416:Nerve Regeneration / Q000528:radiation effects*; D016067:Nerve Transfer; D020221:Optic Nerve Injuries / Q000503:physiopathology*; D012165:Retinal Ganglion Cells / Q000502:physiology / Q000528:radiation effects*; D012235:Rhodamines
D003911:Dextrans; D005456:Fluorescent Dyes; C067661:Fluoro-Ruby; D006133:Growth Substances; D007546:Isoquinolines; D012235:Rhodamines; C017475:lucifer yellow