Affiliations: [a] Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea | [b] Department of Anatomy, Korea University College of Medicine, Brain Korea 21, Seoul, Korea | [c] Department of Physical and Rehabilitation Medicine, Pusan National University College of Medicine, Yangsan Hospital, Pusan, Korea | [d] Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, Seoul, Korea
Correspondence:
[*]
Corresponding author: Yun-Hee Kim, MD, PhD, Professor, Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea. Tel.: +82 2 3410 2824/Ext. 2818; Fax: +82 2 3410 0388; E-mails: yun1225.kim@samsung.com, yunkim@skku.edu
Abstract:
Purpose: Previous studies demonstrated that administering extradural cortical stimulation (ECS) to rats during the acute phase of a photothrombotic infarct enhances motor recovery. However, the effect of ECS during the subacute phase was unknown. We aimed to evaluate the effects of ECS on motor recovery in a rat model of subacute photothrombotic stroke.
Methods: Photothrombotic ischemic injury to the left sensorimotor cortex (SMC) was induced in 41 male Sprague-Dawley rats using Rose-bengal dye (20 mg/kg) and cold light. The rats were randomly divided into two groups: ECS on infarcted SMC (ECS group) and no ECS on infarcted SMC (non-stimulated group). The ECS group received continuous ECS for 14 days starting from day 5 after the stroke onset. Behavioral training with the single-pellet reaching task (SPRT) was performed daily for all of the rats from the fifth day after stroke onset. After 19 days, brain sections were immunostained to allow the quantification of infarct volumes and the evaluation of the neuronal markers.
Results: The SPRT scores showed significantly faster and greater improvement in the ECS group than in the non-stimulated group. There were no significant differences in infarct size. However, in the ECS group, significantly more doublecortin-labeled cells were identified close to the penumbra region of the cerebral cortex.
Conclusions: ECS in the subacute phase improved the behavior motor function in the stroke rat model, and induced a significant axonal sprouting in the peri-infarct area.
Keywords: Axonal sprouting, extradural cortical stimulation, motor recovery, stroke
