title: Pax2+ astrocytes in the fish optic nerve head after optic nerve crush.
abstract: The transcription factor Pax2 actively participates in the development of the vertebrate visual system. In adults, Pax2 expression persists in a subpopulation of Müller cells and/or astrocytes in the retina and optic nerve head (ONH), although its function remains elusive. In a previous work we showed that the pax2 gene expression is modified and the Pax2(+) astrocyte population in the ONH strongly reacted during the regeneration of the retina after a lesion in goldfish. In the present work we have analyzed Pax2 expression in the goldfish ONH after optic nerve (ON) crush. At one week post-injury, when the regenerating axons arrive at the ONH, the pax2 gene expression level increases as well as the number of Pax2(+) astrocytes in this region. These Pax2(+) astrocytes show a higher number of Cytokeratin (Ck)(+)/GFAP(+) processes compared with control animals. In contrast, a different S100(+) astrocyte population is not modified and persists similar to that of controls. Furthermore, we find a ring that surrounds the posterior ONH that is formed by highly reactive astrocytes, positive to Pax2, GFAP, Ck, S100, GS and ZO1. In this region we also find a source of new astrocytes Pax2(+)/PCNA(+) that is activated after the injury. We conclude that Pax2(+) astrocytes constitute a subpopulation of ONH astrocytes that strongly reacts after ON crush and supports our previous results obtained after retina regeneration. Altogether, this suggests that pax2 gene expression and Pax2(+) astrocytes are probably directly involved in the process of axonal regeneration.
authors.affiliation: Institute of Neuroscience of Castilla y Leon, University of Salamanca, Salamanca, Spain; Department of Molecular Neurogenetics, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.mparrillamonge@gmail.com
authors.forename: M
authors.initials: M
authors.lastname: Parrilla
authors.forename: C
authors.initials: C
authors.lastname: Lillo
authors.forename: M J
authors.initials: MJ
authors.lastname: Herrero-Turrión
authors.forename: R
authors.initials: R
authors.lastname: Arévalo
authors.forename: J
authors.initials: J
authors.lastname: Aijón
authors.forename: J M
authors.initials: JM
authors.lastname: Lara
authors.forename: A
authors.initials: A
authors.lastname: Velasco
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D006054:Goldfish; D007150:Immunohistochemistry; D009409:Nerve Crush; D009416:Nerve Regeneration / Q000502:physiology*; D009898:Optic Disk / Q000166:cytology / Q000378:metabolism*; D009900:Optic Nerve / Q000166:cytology / Q000378:metabolism*; D051762:PAX2 Transcription Factor / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D051762:PAX2 Transcription Factor