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Figure 3 Tacrine and duloxetine enhance regeneration of Schwann cells in posterior lateral line axons after Schwann cell ablation. All images are lateral views of the posterior lateral line of (a–e) Tg(mbpa:gal4-vp16;uas:egfp;uas:NTR-mCherry), (f–j) Tg(claudinK:gal4-vp16;uas:megfp;uas:NTR-mCherry) larvae at 8 days post-fertilization (dpf). Anterior to the left and dorsal to the top. (a–e) GFP fluorescence indicates MBP-positive Schwann cells and red fluorescence indicates NTR + Schwann cells or vacuolated Schwann cells. Arrowheads indicate vacuolated cells. (f–j) GFP fluorescence indicates ClaudinK-positive myelin sheaths and blue fluorescence indicates acetylated tubulin-positive PLL axons. Arrows indicate demyelinated axons without GFP + myelin sheaths. (k) Quantification of the number of Schwann cells per 2-somite area. Control: 14 ± 1.79, MTZ: 5.16 ± 1.17, recovery: 6.33 ± 0.37, 100 nM tacrine: 7 ± 1.79, 250 nM tacrine: 9 ± 0.89, 500 nM tacrine: 6.5 ± 1.64, 1 μM duloxetine: 6.5 ± 1.33, 5 μM duloxetine: 9.17 ± 0.32, 10 μM duloxetine: 8.33 ± 1.03. (l) Quantification of the number of vacuolated cells per 2-somite area. Control: 0, MTZ: 5.33 ± 1.86, recovery: 5 ± 1.26, 100 nM tacrine: 2.67 ± 1.21, 250 nM tacrine: 2.67 ± 1.7, 500 nM tacrine: 4.17 ± 0.75, 1 μM duloxetine: 3.83 ± 1.17, 5 μM duloxetine: 2.27 ± 1.03, 10 μM duloxetine: 3.17 ± 1.17. (m) Ratio of the number of myelinated axons is indicated per total number of axons. Control: 1, MTZ: 0.165 ± 0.18, recovery: 0.33 ± 0.18, 100 nM tacrine: 0.39 ± 0.16, 250 nM tacrine: 0.65 ± 0.08, 500 nM tacrine: 0.53 ± 0.14, 1 μM duloxetine: 0.44 ± 0.18, 5 μM duloxetine: 0.78 ± 0.18, 10 μM duloxetine: 0.53 ± 0.2. n = 6 per group. The experiment was independently repeated three times. ***p < 0.001; **p < 0.01; *p < 0.05; n.s., not significant. Scale bar, 25 μm.