Fig. 9

A P2X receptor agonist triggers macroglial activation without inducing RGC injury. a Microglial activation was evaluated by monitoring Aif1 expression 48 h after an intraocular injection of BzATP. This treatment was not found to affect Aif1 mRNA levels relative to PBS-treated retinas (P = 0.21). Additionally, when mice were pre-treated with an intraocular injection of oxATP, a P2X receptor antagonist, prior to optic nerve crush, by 7 days post-crush Aif1 expression by the microglial population not statistically different from PBS-injected retinas (P = 0.20). Data is presented as mean ± SD. For each treatment group, n ≥ 3. b Wild-type mice were treated with an intraocular injection of the P2X receptor agonist, BzATP, which induced a clear increase in Gfap mRNA expression by 48 h. c–e Immunofluorescence of retinal sections confirmed that BzATP triggered an increase in GFAP expression (green label), most obviously in the Müller cell population. The PBS-treated eyes did not exhibit an increase in GFAP. DAPI nuclear counterstain (blue label). Scale bar 50 μm. f The change in Gfap expression after BzATP treatment was also evaluated in Bax ^−/− mice. By 48 h, Gfap expression was elevated in both wild-type and knockout mice, indicative of functional purinergic receptors on Bax-deficient glia. Importantly, markers of RGC injury (Sncg and Nrn1) did not decline, indicating glial activation occurred in the absence of RGC injury. Data is presented as mean ± SD. Ganglion cell layer (GCL). *P < 0.005. For each treatment group and genotype, n ≥ 3