Russian Journal of Developmental Biology

, Volume 49, Issue 5, pp 264–290 | Cite as

The Pax2 and Pax6 Transcription Factors in the Optic Nerve and Brain of Trout Oncorhynchus mykiss after a Mechanical Eye Injury

  • E. V. PushchinaEmail author
  • A. A. Varaksin
  • D. K. Obukhov
Mechanisms of Cell Proliferation and Differentiation


The distribution of the Pax2+ transcription factor in the optic nerve after a mechanical eye injury on the side of damage and in the contralateral nerve has been studied in the trout Oncorhynchus mykiss. It has been found that injury of the optic nerve in this fish species causes Pax2+ reactive astrocytes involved in the initial stages of optic nerve axon regeneration to increase in number, especially in the area of the head and the proximal part of the optic nerve. As the optic nerve in trout is damaged, a significant growth of the heterogeneous population of Pax6+ cells occurs in the brain divisions that have direct retinal inputs, diencephalon, and optic tectum. A part of the Pax6+ cells have an undifferentiated phenotype and are a component of reactive neurogenic niches located in the periventricular zone and parenchymal regions of the brain. Another population of Pax6+ cells has the radial glial phenotype and appears as a result of activation of the constitutive neurogenic domains also within the newly formed reactive neurogenic niches. Thus, due to the optic nerve injury, a pronounced neurogenic response associated with the appearance of reactive neurogenic niches and radial glia arises both in the brain divisions with direct retinal projections and in those lacking the retinal projections as well as in remote regions. The results obtained indicate that the damage to the optic nerve causes an increased reactive neurogenesis in the brain of adult trout.


transcription factor Pax2 Pax6 optic nerve reparative neurogenesis radial glia constitutive and reactive neurogenic niche 









Pax6- immunopositive


ventral zone of the telencephalon ventral region


dorsal zone of the telencephalon ventral region


lateral zone of the telencephalon ventral region


ventral thalamus


optic nerve head


dorsal zone of the telencephalon dorsal region


lateral zone of the telencephalon dorsal region


dorsal thalamus


medial thalamus


central zone of the telencephalon dorsal region


posterior tuberal region




intraorbital segment


cerebellar crest


stratum marginale (marginal layer)


neural stem cell


optic nerve


optical density


optic tectum


periventricular zone


stratum griseum periventriculare (periventricular gray layer)


proliferative zone


magnocellular nucleus of the preoptic region


parvocellular nucleus of the preoptic region


radial glia


reticulospinal cells


reticular formation


stratum album centrale (central white layer)


stratum griseum et album centrale (central gray and white layer)


stratum griseum centrale (central gray layer)


octavolateral efferent neurons


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Copyright information

© Pleiades Publishing, Inc. 2018

Authors and Affiliations

  • E. V. Pushchina
    • 1
    • 2
    Email author
  • A. A. Varaksin
    • 1
  • D. K. Obukhov
    • 3
  1. 1.National Scientific Center of Marine Biology, Far East BranchRussian Academy of SciencesVladivostokRussia
  2. 2.Bogomoletz Institute of PhysiologyNational Academy of Sciences of UkraineKyivUkraine
  3. 3.St. Petersburg UniversitySt. PetersburgRussia

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