Intrinsic activation of PI3K/Akt signaling pathway and its neuroprotective effect against retinal injury

Toru Nakazawa, Masahiko Shimura, Hiroshi Tomita, Hiroshi Akiyama, Yuki Yoshioka, Hideyo Kudou, Makoto Tamai

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78 Citations (Scopus)


Purpose. The aim of this study was to determine whether the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway can function as a neuroprotective pathway following induced retinal injury. Methods. The activation of Akt was assessed by immunoblot analysis, and the role of PI3K/Akt pathway was evaluated by TUNEL staining and counting the number of retrogradely-labeled retinal ganglion cells (RGCs) in the whole retina at 168 h after injury with or without PI3K specific inhibitor, LY294002. Results. Akt was induced within one hr and reached a maximum 6hrs after optic nerve clamping. The activation was observed in the RGC layer including RGCs, the inner plexiform layer, inner nuclear layer, and in the photoreceptor outer segments. The number of surviving RGCs was decreased significantly 168 hrs after injury. LY294002 partially inhibited the activation of Akt, and significantly decreased the number of surviving RGCs as compared with that of injury alone. Conclusions. These results indicate that the PI3K/Akt signaling pathway is activated intrinsically and has a neuroprotective effect on injured RGCs.

Original languageEnglish
Pages (from-to)55-63
Number of pages9
JournalCurrent Eye Research
Issue number1
Publication statusPublished - 2003 Jan


  • Damage
  • Phosphorylation
  • Retinal ganglion cell
  • Signal transduction


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