Egr-1 mRNA expression is a marker for the direction of Mammalian ocular growth

Regan S. Ashby, Guang Zeng, Amelia J. Leotta, Yan Yin Tse, Sally A. McFadden

Research output: Journal article publicationJournal articleAcademic researchpeer-review

16 Citations (Scopus)

Abstract

METHODS. To induce accelerated growth and myopia, guinea pigs wore a -5 diopter (D) lens over one eye from 4 to 11 days of age. To induce inhibited growth, the lens was removed after 7 days of -5 D lens wear, and the eye allowed to recover from myopia for 3 days. Ocular parameters and Egr-1 mRNA levels were subsequently assessed, and compared to untreated fellow eyes and eyes from untreated littermates. Possible circadian changes in Egr-1 mRNA levels were also determined in 18 additional animals by taking measures every 4 hours during a 24-hour cycle.PURPOSE. The immediate early gene Egr-1 is thought to form part of the pathway that mediates abnormal ocular growth. This study investigated whether the mRNA expression levels of Egr- 1 in a mammalian retina are modulated differentially, depending on the direction of ocular growth.RESULTS. Ocular compensation to a -5 D lens occurred after 7 days (D ∆ -4.8 D, D ∆ + 147 lm growth, N = 20). In 5 highly myopic eyes (∆ -7.4 D), Egr-1 mRNA levels in the retina were significantly downregulated relative to contralateral control (51%) and age-matched untreated (47%) eyes. Three days after the -5 D lens was removed, eyes had recovered from the myopia (∆ -0.5 D, relative change of + 2.9 D, N = 4) and Egr-1 mRNA levels were significantly elevated relative to contralateral (212%) and untreated (234%) eyes, respectively. Normal Egr- 1 mRNA expression was higher in the middle of the day than in the middle of the night. Immunolabeling showed strong Egr-1 reactivity in cell bodies in the inner nuclear and ganglion cell layers.CONCLUSIONS. Egr-1 mRNA levels in a mammalian retina show a bi-directional persistent response to opposing ocular growth stimuli. This suggests retinal Egr-1 might act as a signal for the direction of ocular growth in different species.
Original languageEnglish
Pages (from-to)5911-5921
Number of pages11
JournalInvestigative Ophthalmology and Visual Science
Volume55
Issue number9
DOIs
Publication statusPublished - 1 Jan 2014

Keywords

  • Egr-1
  • Guinea pig
  • Myopia
  • Refractive error
  • Retina

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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