Prior Exposure to Immunosuppressors Sensitizes Retinal Microglia and Accelerates Optic Nerve Regeneration in Zebrafish

Figure 2

Local treatment with dex efficiently depletes microglia/macrophages in the inner retina and leaves the optic tectum unaffected. (a-e) A single intravitreal injection of dex causes a transient depletion of retinal microglia in the inner retina. At 6 hpIVT (b), microglia are still present, but they seem to have retracted their processes. At 1 and 2 dpIVT (c-d), the inner retina is almost devoid of microglia, while at 3 dpIVT (e), repopulation of the retina is ongoing. (f-j) Intravitreal injection of dex does not affect the microglial number or their appearance in the optic tectum. The outer tectal layers, i.e., the stratum opticum (SO) and the stratum fibrosum et griseum superficiale (SFGS), are indicated. Scale bars: 50 μm.