Integrin survival signaling is down-regulated in RGC in the retina 1 day after ischemic injury. A.

<p>(<b>i</b> ) Western blot of retinal extracts of ischemic, RIRI (+), and control (−) rat eyes 1 day post-injury (n = 3). A representative example of at least 5 independent experiments is presented. (<b>ii</b>) Densitometric analysis of western blotting with all samples normalized to β-actin. Error bars, SD. Student’s <i>t</i> test. *p<0.05. <b>B.</b> β1 integrin expression is decreased in RGC 1 day post-RIRI. Immunohistochemistry with β1 integrin antibodies (red) in frozen retinal sections from control (<b>a, b, c</b>), and ischemic retinas (<b>d, e, f</b>), in which RGCs were retrogradely labeled with FG (green; <b>a, d</b>) shows reduced β1 integrin expression in ischemic eyes in comparison with control eyes (red; <b>b, e</b>) specifically in RGC (yellow; merged; <b>c, f</b>). Nuclei are stained with DAPI (blue; <b>c, f</b>). (n = 12). GCL = ganglion cell layer, INL = inner nuclear layer. Scale bars: 10 µm. <b>C.</b> FAK activation is reduced in RGC 1 day after ischemia. Immunohistochemistry with FAK (purple), and P-FAK [pY<sup>397</sup>] (red) antibodies in frozen retinal sections of control (<b>a, b, c)</b>, and ischemic retinas (<b>d, e, f</b>) at 1 day post-RIRI, in which RGCs were retrogradely labeled with FG (yellow; <b>a, d</b>) shows significantly decreased expression of the activated, phospho [pY<sup>397</sup>] FAK in ischemic eyes in comparison with control eyes (red; <b>c, f</b>), while FAK expression remains unchanged (purple; <b>b, e</b>). White arrows identify FG labeled RGCs in the control retina (CTRL) expressing high levels of both FAK, and P-FAK [pY<sup>397</sup>] (<b>a, b, c</b>). Blue arrows point toward RGCs in the ischemic retina (RIRI) that have markedly decreased expression of P-FAK [pY<sup>397</sup>], while FAK expression is the same (<b>d, e, f</b>). (n = 12). GCL = ganglion cell layer, INL = inner nuclear layer. Scale bars: 10 µm.</p>