Figure 4.

Acute Inhibition of Autophagy in Aged Mice Exacerbates Features of Sarcopenia and NMJ Degeneration

(A) Immunoblotting for LC3 and p62 proteins on muscle extracts from 25-month-old tamoxifen-inducible Atg7^−/− female mice. Three months after the tamoxifen treatment, skeletal muscles were collected and analyzed.

(B) Acute inhibition of autophagy in old mice induces muscle degeneration. Quantification of the CSA of myofibers in TA muscles of aged tamoxifen-inducible Atg7^−/− and Atg7^f/f mice. Values are mean ± SEM; at least five muscles of each group were analyzed.

(C) Quantification of center-nucleated myofibers in TA of tamoxifen-inducible Atg7^−/− (n > 5 for each group; ^∗p < 0.05). Values are mean ± SEM.

(D) Acute inhibition of Atg7 in aged female mice increases the number of denervated NCAM-positive fibers when compared to age-matched controls. Values were normalized for the total number of myofibers in muscle section (at least five muscles of each group were analyzed; ^∗p < 0.05). Values are mean ± SEM.

(E) Expression levels of MuSK after acute inhibition of Atg7 in old mice. MuSK is upregulated in aged tamoxifen-inducible Atg7^−/− muscles (^∗p < 0.05; n > 5). Values are mean ± SEM.

(F) Acute inhibition of autophagy in aged mice led to an increased amount of diffused MuSK staining; at least four muscles of each group were analyzed; ^∗∗∗p < 0.001. Values are mean ± SEM.