Abstract
Abstract: :
Purpose: Akt2 is one of three isoforms of the Akt family, which plays important roles in cell protection, proliferation, growth and glucose metabolism. We have studied the retinal phenotype of Akt2 knockout (KO) mice and the putative anti–apoptosis role of Akt2 in the light–induced apoptosis. Methods: C56Bl/6 Akt2 KO heterozygous mice were bred to BalbC mice to generate the Akt2 KO in an albino background. Sixth generation KO, heterozygous, and wild type (WT) of 7–8 weeks of age were placed under 2,700 lux continuous illumination for 24 hours. Retinal function was determined by ERG. Photoreceptor cell death was determined by measuring the outer nuclear layer thickness and TUNEL staining in paraffin–embedded sections Results: Prior to constant light exposure, retinal ERG and morphology were not significantly different among Akt2 KO, Akt2 heterozygous, and WT mice. However, after light stress, the thickness of outer nuclear layer was less in the Akt2 KO mice than in heterozygous or WT mice. ERG analysis showed a reduction in amplitudes in the KO mice. TUNEL analysis showed more positive cells in the KO group than the WT group after the intense light exposure. Conclusions: There is no significant change in structure or function in Akt2 KO mice retina compared to Akt2 heterozygous or WT mice. However, Akt2 KO mice appear to be more sensitive to acute light stress than WT mice, which suggests a neuroprotective role for Akt2 in the retina.
Keywords: transgenics/knock-outs • apoptosis/cell death • retinal degenerations: cell biology