Effects of ursolic acid on sub-lesional muscle pathology in a contusion model of spinal cord injury

PLoS One. 2018 Aug 29;13(8):e0203042. doi: 10.1371/journal.pone.0203042. eCollection 2018.

Abstract

Spinal Cord Injury (SCI) results in severe sub-lesional muscle atrophy and fiber type transformation from slow oxidative to fast glycolytic, both contributing to functional deficits and maladaptive metabolic profiles. Therapeutic countermeasures have had limited success and muscle-related pathology remains a clinical priority. mTOR signaling is known to play a critical role in skeletal muscle growth and metabolism, and signal integration of anabolic and catabolic pathways. Recent studies show that the natural compound ursolic acid (UA) enhances mTOR signaling intermediates, independently inhibiting atrophy and inducing hypertrophy. Here, we examine the effects of UA treatment on sub-lesional muscle mTOR signaling, catabolic genes, and functional deficits following severe SCI in mice. We observe that UA treatment significantly attenuates SCI induced decreases in activated forms of mTOR, and signaling intermediates PI3K, AKT, and S6K, and the upregulation of catabolic genes including FOXO1, MAFbx, MURF-1, and PSMD11. In addition, UA treatment improves SCI induced deficits in body and sub-lesional muscle mass, as well as functional outcomes related to muscle function, motor coordination, and strength. These findings provide evidence that UA treatment may be a potential therapeutic strategy to improve muscle-specific pathological consequences of SCI.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Disease Models, Animal
  • Female
  • Gene Expression / drug effects
  • Mice, Inbred C57BL
  • Motor Skills / drug effects
  • Muscle Strength / drug effects
  • Muscle, Skeletal / drug effects*
  • Muscle, Skeletal / pathology
  • Muscle, Skeletal / physiopathology
  • Organ Size
  • Protective Agents / pharmacology*
  • Random Allocation
  • Spinal Cord Injuries / drug therapy*
  • Spinal Cord Injuries / pathology
  • Spinal Cord Injuries / physiopathology
  • Triterpenes / pharmacology*
  • Ursolic Acid

Substances

  • Protective Agents
  • Triterpenes

Grants and funding

This work was supported by the Miami Project to Cure Paralysis. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.