Enriched rehabilitative training promotes improved forelimb motor function and enhanced dendritic growth after focal ischemic injury

J Neurosci. 2001 Jul 15;21(14):5272-80. doi: 10.1523/JNEUROSCI.21-14-05272.2001.

Abstract

Chronic impairment of forelimb and digit movement is a common problem after stroke that is resistant to therapy. Previous studies have demonstrated that enrichment improves behavioral outcome after focal ischemia; however, postischemic enrichment alone is not capable of enhancing fine digit and forelimb function. Therefore, we combined environmental enrichment with daily skilled-reach training to assess the effect of intensive task-specific rehabilitation on long-term functional outcome. Rats were subjected to either endothelin-1-induced focal ischemia or sham surgery and subsequently designated to enriched-rehabilitation or standard-housing treatment groups starting 15 d after ischemia. Functional assessment of the affected forelimb at 4 and 9 weeks after treatment revealed that ischemic plus enrichment (IE) animals had improved approximately 30% on the staircase-reaching task and were indistinguishable from sham animals for both latency and foot faults in a beam-traversing task. In contrast, ischemic plus standard (IS) animals remained significantly impaired on both tasks. Interestingly, both ischemic groups (IE and IS) relied on the nonaffected forelimb during upright weight-bearing movements, a pattern that persisted for the duration of the experiment. Dendritic arborization of layer V pyramidal cells within the undamaged motor cortex was examined using a Golgi-Cox procedure. IE animals showed enhanced dendritic complexity and length compared with both IS and sham groups. These results suggest that enrichment combined with task-specific rehabilitative therapy is capable of augmenting intrinsic neuronal plasticity within noninjured, functionally connected brain regions, as well as promoting enhanced functional outcome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain Ischemia / chemically induced
  • Brain Ischemia / physiopathology
  • Brain Ischemia / rehabilitation*
  • Dendrites* / physiology
  • Disease Models, Animal
  • Environment
  • Forelimb / physiopathology*
  • Male
  • Motor Skills*
  • Neuronal Plasticity
  • Physical Therapy Modalities / methods*
  • Rats
  • Rats, Sprague-Dawley
  • Reaction Time
  • Recovery of Function
  • Treatment Outcome