Figure 7

DRP1 inhibition prevents axonal degeneration and astroglial activation in the glial lamina of glaucomatous D2 mice. (a) GFAP and neurofilament double immunohistochemistry. Overexpression of DRP1^K38A partially preserved neurofilament and GFAP immunoreactivities in the glial lamina of glaucomatous D2 mice. Scale bar: 20 μm (a, upper panels); 5 μm (a, lower panels). (b) The origin of the cross-sections in a is shown in the glial lamina from the longitudinal section of D2-Gpnmb⁺ mice (open bar). (c) Quantitative analysis showed that overexpression of DRP1^K38A significantly preserved GFAP immunoreactivity in the glial lamina of glaucomatous D2 mice. Values are mean±S.D. *Significant at P<0.05 compared with D2-Gpnmb⁺ mice transduced with AAV2-Null or glaucomatous D2 mice transduced with AAV2-Null. Conventional transmission electron microscopy (TEM) analysis. (d) D2-Gpnmb⁺mice transduced with AAV2-Null showed normal healthy morphology of myelinated axons in the ON. In contrast, glaucomatous D2 mice transduced with AAV2-Null showed the absence of axons, as well as accumulation and disorganization of myelination in the ON. It is noteworthy that abundant hypertrophic astrocyte processes filled in the area of axon loss. However, overexpression of DRP1^K38A showed the preservation of axon structure and myelination in the ON of glaucomatous D2 mice. Scale bar: 2 μm (all panels). (e) Schematic representation with the ON region of 2D EM data collection from the longitudinal section of D2-Gpnmb⁺ mice (bar). (f) Quantitative analyses showed that overexpression of DRP1^K38A significantly increased the number of axons in the ON of glaucomatous D2 mice (n=26 images). Values are mean±S.D. *Significant at P<0.05 compared with D2-Gpnmb⁺mice transduced with AAV2-Null; **Significant at P<0.01 compared with D2-Gpnmb⁺mice transduced with AAV2-Null or glaucomatous D2 mice transduced with AAV2-Null