Figure 4.

Neutrophil depletion decreases Ocm levels in the retina and suppresses optic nerve regeneration. A–H, Immunostaining for the indicated growth factors 1 d after intraocular injection of zymosan and systemic treatment with control IgG (A, C, E, G) or anti-Ly6G (B, D, F, H). I, Quantitation of immunoreactivity. Control IgG did not alter immunostaining for any of the factors, whereas anti-Ly6G selectively diminished immunostaining for Ocm (†p < 0.05; n ≥ 4 for each condition). J–M, Effect of neutrophil depletion on optic nerve regeneration. GAP-43⁺ axons are visualized by immunostaining in longitudinal sections through the mouse optic nerve 2 weeks after nerve injury and intraocular zymosan injections. Asterisks denote the injury site. Whereas treatment with control IgG had no effect (compare K, J), immune depletion of neutrophils with the anti-Ly6G antibody suppressed regeneration (L). M, Quantitation. ***Increase relative to negative controls (optic nerve crush alone) significant at p < 0.001. †Decrease relative to controls treated with normal IgG significant at p < 0.05. Results are based on N ≥ 4 cases per condition. Scale bar: A–H, 50 μm.