A modified rehabilitation paradigm bilaterally increased rat extensor digitorum communis muscle size but did not improve forelimb function after stroke

PLoS One. 2024 Apr 11;19(4):e0302008. doi: 10.1371/journal.pone.0302008. eCollection 2024.

Abstract

Malnutrition after stroke may lessen the beneficial effects of rehabilitation on motor recovery through influences on both brain and skeletal muscle. Enriched rehabilitation (ER), a combination of environmental enrichment and forelimb reaching practice, is used preclinically to study recovery of skilled reaching after stroke. However, the chronic food restriction typically used to motivate engagement in reaching practice is a barrier to using ER to investigate interactions between nutritional status and rehabilitation. Thus, our objectives were to determine if a modified ER program comprised of environmental enrichment and skilled reaching practice motivated by a short fast would enhance post-stroke forelimb motor recovery and preserve forelimb muscle size and metabolic fiber type, relative to a group exposed to stroke without ER. At one week after photothrombotic cortical stroke, male, Sprague-Dawley rats were assigned to modified ER or standard care for 2 weeks. Forelimb recovery was assessed in the Montoya staircase and cylinder task before stroke and on days 5-6, 22-23, and 33-34 after stroke. ER failed to improve forelimb function in either task (p > 0.05). Atrophy of extensor digitorum communis (EDC) and triceps brachii long head (TBL) muscles was not evident in the stroke-targeted forelimb on day 35, but the area occupied by hybrid fibers was increased in the EDC muscle (p = 0.038). ER bilaterally increased EDC (p = 0.046), but not TBL, muscle size; EDC muscle fiber type was unchanged by ER. While the modified ER did not promote forelimb motor recovery, it does appear to have utility for studying the role of skeletal muscle plasticity in post-stroke recovery.

MeSH terms

  • Animals
  • Disease Models, Animal
  • Forelimb
  • Humans
  • Male
  • Muscle, Skeletal
  • Rats
  • Rats, Sprague-Dawley
  • Recovery of Function / physiology
  • Stroke Rehabilitation*
  • Stroke*

Grants and funding

This work was supported by the Canadian Institutes of Health Research (https://cihr-irsc.gc.ca)/Heart and Stroke Foundation of Canada (https://www.heartandstroke.ca/what-we-do/research/for-researchers) Synchrotron Medical Imaging Team Grant no. CIF 99472 [PGP, FC] and the Canadian Institutes of Health Research (Grants 111124 [PGP] and 159813 [PGP, FC, GDM, MA]). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.