Figure 1
Day/night expression of clock genes. Day/night expression profiles of clock genes in gastrocnemius (A) and soleus (B) muscles of 7 – 8 month-old (adult) f/f and M-KO mice at ZT1 and ZT13. Data are shown as means ± SEM (f/f; n = 6, M-KO; n = 4 at each ZT). Value for f/f mice at ZT1 is expressed as 1.0. *P < 0.05 and **P < 0.01 for f/f vs. M-KO mice. Ga, gastrocnemius; Sol, soleus.
Figure 2
Extent of denervation-induced gastrocnemius (Ga) muscle atrophy in muscle specific-Bmal1 knockout (M-KO) and littermate control (f/f) mice. (A) Relative Ga muscle mass of 7 – 8-month-old (adult) f/f and M-KO mice at seven days after denervation. Sciatic nerves in left hind legs were dissected and contralateral hind legs served as controls. Value for contralateral Ga muscle weight/body weight in f/f mice is shown as 100%. (B) Expression of mRNA for genes associated with muscle atrophy or degeneration in Ga muscle at seven days after denervation. Data are expressed as means ± SEM (f/f; n = 11, M-KO; n = 9). The value for contralateral muscle of f/f mice is expressed as 1.0. *P < 0.05 and **P < 0.01 for contralateral vs. denervated muscles. †P < 0.05 and ††P < 0.01 for f/f vs. M-KO mice. Ga, gastrocnemius muscle.
Figure 3
Extent of soleus (Sol) muscle atrophy induced by denervation in muscle-specific Bmal1 knockout (M-KO) mice and littermate control (f/f) mice. (A) Relative Sol muscle mass of 7 – 8-month-old (adult) f/f and M-KO mice at seven days after denervation. Sciatic nerves in left hind legs were dissected and contralateral legs served as a control. Value of contralateral Sol muscle weight/body weight in f/f mice is shown as 100%. (B) Messenger RNA expression of genes associated with muscle atrophy or degeneration in Sol muscle at seven days after denervation. Data are expressed as means ± SEM (f/f, n = 11; M-KO, n = 9). Value for contralateral muscle of f/f mice is expressed as 1.0. *P < 0.05 and **P < 0.01 for contralateral vs. denervated muscle. †P < 0.05 and ††P < 0.01 for f/f vs. M-KO mice. Sol, soleus.
Figure 4
Extent of muscle atrophy induced by aging in muscle-specific Bmal1 knockout (M-KO) mice and littermate control (f/f) mice. Relative gastrocnemius (Ga) (A) and soleus (Sol) (C) muscle mass of 7 – 8-month-old (adult) and 23 – 24-month-old (aged) f/f and M-KO mice, respectively. Ratio of muscle weight/body weight of adult f/f mice is shown as 100%. Messenger RNA expression of genes associated with muscle atrophy or degeneration in Ga (B) and Sol (D) muscles. Data are expressed as means ± SEM (adult f/f, n = 10; adult M-KO, n = 8; aged f/f, n = 6; aged M-KO; n = 6). The value for adult f/f mice is expressed as 1.0. *P < 0.05 and **P < 0.01 for adult vs. aged mice. †P < 0.05 and ††P < 0.01 for f/f vs. M-KO mice. Ga, gastrocnemius; Sol, soleus.