Fig. 6
Long-lasting poly-innervation after NMJ short-term reinnervation of the LAL muscle. LAL muscles from control adult mice and from different times after nerve crush injury were dissected and subjected to immunofluorescence staining to reveal presynaptic motor axons and terminals (magenta) along with Alexa 488-BTX (cyan) to stain postsynaptic densities. a Representative images of denervated postsynaptic domains (arrows) at 5d and multiple axons innervating one postsynaptic domain after reinnervation (arrowheads) at different times after NMJ reinnervation. Bar = 20 μm. b The proportion of poly-innervated NMJs in LAL muscles from control and nerve-injured mice at the indicated times was quantified and expressed as the percentage of total NMJs. c Poly-innervated NMJs exhibiting pretzel-like (green), fragmented (gray), and collapsed (red) morphologies from control and nerve-injured mice at the indicated times were quantified and expressed as the percentage of total poly-innervated NMJs per animal. Green and gray asterisks show significant differences between pretzel-like and fragmented morphologies, respectively. d Poly-innervated NMJs displaying smooth (blue bars) and blurred fragmented (purple bars) morphologies in LAL muscles from control and nerve-injured mice at different times are expressed as the percentage of total fragmented NMJs. The results are represented as the mean ± SEM (c, d) along with each individual value (b) (N: 3–4 mice; 2 female plus 1–2 male mice). *p < 0.05, **p < 0.01, ***p < 0.001, one-way ANOVA test (b), or two-way ANOVA (c, d)