Expression of the CT transgene in mdx muscles inhibits elevations in
serum creatine kinase activity. Serum creatine kinase activity was
measured in Wt, CT, mdx, and mdx/CT animals at various ages. Serum
creatine kinase activity was increased in mdx mice by an order of
magnitude compared with Wt mice (P < 0.001 for
all). Serum creatine kinase activity was reduced in mdx/CT mice
(P < 0.001, compared with mdx, for all) and was
not significantly different from wild-type levels
(P > 0.05). For Wt, n = 40 (5
weeks) and 15 (6 months); CT, n = 32 (5 weeks) and
12 (6 months); mdx, n = 14 (5 weeks), 10 (3
months), and 14 (6 months); mdx/CT, n = 10 (5
weeks), 8 (3 months), and 14 (6 months).