Mechanical Axon Insult, but Not Excitotoxicity, Induces BAX-Dependent RGC Death

<p>To help distinguish between the likely roles of mechanical axon insult and excitotoxicity in cell death induction in spontaneous glaucoma, we subjected preglaucomatous DBA/2J mice of each <i>Bax</i> genotype to either controlled optic nerve crush or NMDA-mediated excitotoxicity. For controlled crush and NMDA, the percent RGC survival in the manipulated eye compared to the contralateral control eye is shown. For ease of comparison, the data for glaucomatous damage are the same as shown in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.0010004#pgen-0010004-g003" target="_blank">Figure 3</a>. In contrast to the spontaneous glaucoma, NMDA-mediated RGC death is not dependent on BAX, as evident by the complete lack of protection from death in <i>Bax</i>^−/− mice. As for the spontaneous glaucoma, RGC death induced by controlled optic nerve crush was completely dependent on BAX and prevented in both <i>Bax</i>^+/− and <i>Bax</i>^−/− mice. Overall, the effects of BAX in the face of spontaneous glaucoma and controlled crush were remarkably similar.