myelin-basic-protein and helenalin

To characterize a model of optic nerve axonal degeneration induced by tumor necrosis factor (TNF)-alpha and to determine the role of nuclear factor (NF)-kappaB p65 in axonal degeneration.. Groups of rats were euthanatized at 1 day, 1 or 2 weeks, or 1 or 2 months after intravitreal injection of TNF-alpha. Morphometric analyses of neurofilament- or Thy-1-positive cells, retinal ganglion cells (flat preparations stained with cresyl violet or retrograde labeling with a neurotracer), the number of axons, immunostaining for myelin basic protein, and TUNEL assays were performed. Levels of NF-kappaB p65 protein in retina and optic nerve were determined by Western blot analysis and immunohistochemistry. The effects of antisense oligodeoxynucleotide (AS ODN) against NF-kappaB p65 and helenalin, an inhibitor of NF-kappaB p65 activation, on TNF-alpha-induced optic nerve degeneration were determined by counting the number of axons.. Intravitreal injections of TNF-alpha induced obvious axonal loss and extensive degeneration of the axons from 2 weeks to 2 months after injection, whereas significant retinal ganglion cell loss was noted only at 2 months after injection. NF-kappaB p65 was increased in the optic nerve but not in the retina and was found to colocalize with ED-1 and Iba1, markers of microglia. Inhibition of NF-kappaB p65 with AS ODN or helenalin significantly ameliorated the effects of TNF-alpha-mediated axonal loss.. TNF-alpha causes axonal degeneration with probable delayed loss of retinal ganglion cell bodies. NF-kappaB p65 may play a pivotal role in axonal degeneration, with the possible involvement of microglial cells.

Topics: Animals; Axons; Blotting, Western; Immunohistochemistry; In Situ Nick-End Labeling; Injections; Male; Myelin Basic Protein; Nerve Degeneration; Oligodeoxyribonucleotides, Antisense; Optic Nerve; Rats; Rats, Inbred Lew; Retina; Sesquiterpenes; Sesquiterpenes, Guaiane; Transcription Factor RelA; Tumor Necrosis Factor-alpha; Vitreous Body