Preconditioning with bright light evokes a protective response against light damage in the rat retina

Changdong Liu, Min Peng, Alan M. Laties, Rong Wen

Research output: Contribution to journalArticlepeer-review

153 Scopus citations


Constant exposure to bright light induces photoreceptor degeneration and at the same time upregulates the expression of several neurotrophic factors in the retina. At issue is whether the induced neurotrophic factors protect photoreceptors. We used a preconditioning paradigm to show that animals preconditioned with bright light became resistant to subsequent light damage. The preconditioning consisted of a 12-48 hr preexposure, followed by a 48 hr 'rest phase' of normal cyclic lighting. The greatest protection was achieved by a 12 hr preexposure. Preconditioning induces a prolonged increase in two endogenous neurotrophic factors: basic fibroblast growth factor (bFGF) and ciliary neurotrophic factor (CNTF). It also stimulates the phosphorylation of extracellular signal-regulated protein kinases (Erks) in both photoreceptors and Muller cells. These findings indicate that exposure to bright light initiates two opposing processes: a fast degenerative process that kills photoreceptors and a relatively slower process that leads to the protection of photoreceptors. The extent of light damage, therefore, depends on the interaction of the two processes. These results also suggest a role of endogenous bFGF and CNTF in photoreceptor protection and the importance of Erk activation in photoreceptor survival.

Original languageEnglish (US)
Pages (from-to)1337-1344
Number of pages8
JournalJournal of Neuroscience
Issue number4
StatePublished - Feb 15 1998
Externally publishedYes


  • bFGF
  • CNTF
  • Degeneration
  • Erk
  • Light damage
  • Muller cell
  • Photoreceptor
  • Rat
  • Retina

ASJC Scopus subject areas

  • Neuroscience(all)


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