Fig. 6

A necessary role of muscle activity for Lrp4 β-gal synaptic localization in aged mice. a Scheme of electric stimulation of muscle. b Lrp4 β-gal was diffused in aged muscles but became localized at NMJ after electric stimulation of muscle. Red arrow: NMJ localization. Scale bar, 0.8 mm. c Quantification of Lrp4 β-gal across muscle fibers (the red dotted line of b). Triangle indicates NMJ localization. d Synaptic Lrp4 β-gal distribution revealed by surface plot analysis. Scale bar, 20 µm. e Increased mRNA of lacZ and Lrp4 in aged muscles but reduced by stimulation. *p < 0.05 (*lacZ = 0.019, *Lrp4 = 0.0398), ****p < 0.0001. n = 4 mice per group, one-way ANOVA. M: month; S: stimulation; 27S: 27M+S