Fig. 2

(A) Experimental pipeline to examine regeneration phenotypes after SCI.

(B) Swim endurance assays determined baseline motor function for uninjured mstnb^−/+, mstnb^−/−, and wild-type fish.

(C) Swim endurance assays for mstnb^−/+, mstnb^−/−, and wild-type fish at 14, 28, and 42 dpi. Statistical analyses of swim times are shown for mstnb^−/+ (gray) and mstnb^−/− (magenta) relative to wild types. Recovery of mstnb^−/− animals was not significantly different between 14 and 42 dpi.

(D–F) Swim behavior assays assessed the performance of mstnb^−/+, mstnb^−/−, and wild-type siblings at minimal water current velocity. Average Y position in the tunnel (D), percent activity (E), and burst frequency (F) were quantified at 10 cm/s water current velocity. mstnb^−/+, mstnb^−/−, and wild-type fish are shown at 14, 28, and 42 dpi. Statistical analyses of swim times are shown for mstnb^−/+ (gray) and mstnb^−/− (magenta) relative to wild types. Two independent experiments are shown.

(G) Glial bridging in mstnb^−/− (magenta) and wild-type siblings (gray) at 14 dpi. Representative immunohistochemistry shows the Gfap⁺ bridge at the lesion site. Percent bridging represents the cross-sectional area of the glial bridge at the lesion site relative to the intact SC. Percent bridging was quantified for 5–7 animals per group.

(H) Anterograde axon tracing in mstnb−/− (magenta) and wild-type zebrafish (gray) at 28 dpi. The biocytin axon tracer was applied rostrally and analyzed at 500 μm (proximal) and 1,500 μm (distal) caudal to the lesion. Axon growth was normalized to biocytin labeling in wild-type controls at the proximal level. Quantification represents 7–9 animals per group.

(I) Retrograde axon tracing in mstnb^−/− (magenta) and wild-type zebrafish (gray) at 21 dpi. The biocytin axon tracer was applied caudally, and biocytin-labeled neuronal cell bodies were analyzed 150 μm (proximal) and 450 μm (distal) rostral to the lesion.

Dots represent individual animals from 2 or 3 independent clutches, and error bars depict SEM. Quantification represents 8–9 animals per group. *p < 0.05; **p < 0.01; ***p < 0.001; ns, p > 0.05. Scale bars, 50 μm.