Direct effects of glucocorticoids in ependymal glia. (A–I) Zebrafish spinal cord transverse sections. (A–C) Immunostaining of wild-types for Nr3c1 (green) and Gfap (red), plus DAPI staining (blue) with Dex treatment at 24 h post sham injury (A), 24 h (B) and 48 h post SCI (C). Nuclear Nr3c1 (active) localization in Gfap-positive cells around the central canal is stimulated with Dex treatment. (D–F) Immunostaining for EGFP (pan-cytoplasmic) in the SR4G transgenic reporter line (green) and filamentous Gfap (red) at 24 h post sham injury (D) and SCI with no treatment (E) or 24 h post SCI +Dex (F). Nr3c1 signaling is constitutively active in ependymal glia in uninjured controls (D), diminished after SCI (E), and was maintained after SCI + Dex. (G–I) Immunostaining for Sox2 (green), PCNA (red) and Gfap (blue) from 48 h post sham injury (G), 48 h post SCI followed by no treatment (H), or 48 h post SCI +Dex (I). Sox2 immunoreactivity is reduced in ependymal glia and neural precursor cells after Dex treatment. Representative images from 10 spinal cords per time point in each condition. Scale bars, 20 μm (A is the same as B,C; D is the same as E,F; G is the same as H,I). ∗denotes central canal.
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