Affiliations: Center for Neuroscience Research, SMART Institute of Advanced Biomedical Science, Konkuk University, Seoul, Korea | Department of Medical Science, Konkuk University School of Medicine, Seoul, Korea | Department of Rehabilitation Medicine, Konkuk University Medical Center and Konkuk University School of Medicine, Seoul, Korea
Note: [] Corresponding author: Dong-Hee Choi, Ph.D., Center for Neuroscience Research, SMART Institute of Advanced Biomedical Science, Department of Medical Science, Konkuk University School of Medicine, Seoul 143-701, Korea. Tel.: +82 22049 6012; Fax: +82 22030 7899; E-mail: dchoi@kku.ac.kr
Note: [] Corresponding author: Jongmin Lee, M.D., Ph.D., Center for Neuroscience Research, SMART Institute of Advanced Biomedical Science, Department of Rehabilitation Medicine, Konkuk University School of Medicine, Seoul 143-701, Korea. Tel.: +82 22030 5345; Fax: +82 22030 7899; E-mail: leej@kuh.ac.kr
Abstract: Purpose: To determine the optimal timing of rehabilitation and its role in corticospinal tract (CST) plasticity after stroke. Methods: Rats were subjected to photothrombotic infarct. The large stroke (LS) and small stroke (SS) groups were subdivided and task-specific training (TST) was initiated at 1, 5, or 14 days poststroke. Behavioral tests were performed at 2, 7, 14, 21, 28, and 35 days poststroke. The differences of axonal sprouting in the cortex, red nucleus, cerebral peduncle, and pyramid level were compared by immunohistochemistry. Results: SS groups with TST starting at 1 day and 5 days showed significantly better recovery in the behavioral tests. LS group with TST starting at 5 days showed better recovery, while those with TST starting at 1 day showed worse recovery. Contralesional axonal sprouting was increased in both groups with TST starting at 5 days. However, it was decreased in the LS group with TST starting at 1 day. Transcallosal axonal sprouting from the contralesional motor cortex was increased in the LS group with TST starting at 5 days. Conclusions: Functional recovery after stroke may vary, depending on the lesion size and the timing of rehabilitation. The underlying mechanism may involve contralesional CST plasticity and transcallosal axonal sprouting.
