Soluble activin receptor type IIB increases forward pulling tension in the mdx mouse

Muscle Nerve. 2011 May;43(5):694-9. doi: 10.1002/mus.21944. Epub 2011 Apr 1.


Introduction: In this study we investigated the action of RAP-031, a soluble activin receptor type IIB (ActRIIB) comprised of a form of the ActRIIB extracellular domain linked to a murine Fc, and the NF-κB inhibitor, ursodeoxycholic acid (UDCA), on the whole body strength of mdx mice.

Methods: The whole body tension (WBT) method of assessing the forward pulling tension (FPT) exerted by dystrophic (mdx) mice was used.

Results: RAP-031 produced a 41% increase in body mass and a 42.5% increase in FPT without altering the FPT normalized for body mass (WBT). Coadministration of RAP-031 with UDCA produced increases in FPT that were associated with an increase in WBT.

Conclusions: Myostatin inhibition increases muscle mass without altering the fundamental weakness characteristic of dystrophic muscle. Cotreatment with an NF-κB inhibitor potentiates the effects of myostatin inhibition in improving FPT in mdx mice.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activin Receptors, Type II / pharmacology
  • Activin Receptors, Type II / physiology*
  • Animals
  • Female
  • Male
  • Mice
  • Mice, Inbred mdx
  • Muscle Contraction / drug effects
  • Muscle Contraction / physiology
  • Muscle Tonus / drug effects
  • Muscle Tonus / physiology*
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / physiology*
  • Muscular Dystrophy, Animal / genetics
  • Muscular Dystrophy, Animal / physiopathology*
  • Solubility


  • Activin Receptors, Type II
  • activin receptor type II-B