TNF-α induces SARM1-dependent axon loss and RGC death in a neuroinflammatory model of glaucoma. (A) Schematic diagram of TNF-α intravitreal (I.V.) injection. Axons and cell bodies are quantified at 2 wk (2w) or 2 mo (2m) following TNF-α or PBS injection. (B) EM of WT and SARM1 KO optic nerves at 2 mo after PBS or TNF-α injection. Scale bar, 2 µm. (C and D) Quantification of axon number (C) and axon size (D) in the optic nerve of WT or SARM1 KO mice at 2 wk (2w) or 2 mo (2m) after intravitreal injection of PBS or TNF-α. Data represent the mean ± SEM; n = 4 or 5 for each condition; (C) axon number: one-way ANOVA with post hoc Tukey test, F(7,30) = 21.1, P < 0.0001; (D) axon size: One-way ANOVA with post hoc Tukey test, F(7,34) = 15.27, P < 0.0001; *, P < 0.05; **, P < 0.01; and ***, P < 0.001. (E) Histograms of the range of axon diameter at 2 wk (2w, left) and 2 mo (2m, right). Data are the same as used in C and D. (F) Representative Brn3a immunostaining of WT and SARM1 KO retinas at 2 mo after TNF-α injection. Scale bar, 50 µm. (G) Quantification of the number of Brn3a-positive RGCs in WT or SARM1 KO retina at 2 wk (2w) or 2 mo (2m) after PBS or TNF-α intravitreal injection. Data represent the mean ± SEM; n = 4–7 for each condition; One-way ANOVA with post hoc Tukey test, F(7,36) = 13.2, P < 0.0001; *, P < 0.05; **, P < 0.01; and ***, P < 0.001.