Single intramuscular injection of Vivo-PMO-mstn in C57BL10 mice increases muscle
mass. Vivo-PMO-mstn (10 µg) was injected into the left tibialis anterior
(TA) of C57BL10 mice (n = 6). The contralateral muscle was injected with
excipient. Mice were killed after 1, 2, 4, and 8 weeks. (a) Representative
products of nested RT-PCR analysis of myostatin exon 2 skipping in treated and control
muscles at 1, 2, 4 or 8 weeks after the injection are shown. (b) Densitometric
analyses of nested RT-PCR products of myostatin exon 2 skipping in treated and control
muscles at 1, 2, 4 or 8 weeks (n = 6). Levels of exon skipping declined 8 weeks
after the injection. Both bands corresponding to skipped products were included in the
analysis. (c) Change in TA muscle mass following a single intramuscular injection
of Vivo-PMO-mstn after 1, 2, 4 or 8 weeks. (Two-tailed t-test, *P
= 0.0404; **P = 0.005, n = 6). (d) Representative TA
muscles collected 8 weeks after a single injection of saline (left) or Vivo-PMO-mstn
(right). Proximal (prox), central (central), and distal (dist) levels of the muscles are
indicated by yellow lines. ns, not significant; PMO, phosphorodiamidate morpholino
oligomer; RT-PCR, reverse transcription-PCR.