Purpose: Constraint-induced movement therapy (CIMT) can improve motor functions in stroke patients and ischemic rats. This study examined the effect of CIMT in ischemic rats using positron emission tomography (PET).
Methods: We used middle cerebral artery occlusion (MCAO) procedure to induce cerebral ischemia in rats. Male rats were divided into a negative control group (Normal, n = 4), a sham-operated group (Sham, n = 6), an ischemic group (Control, n = 6) and an ischemic CIMT-treated group (CIMT, n = 6). CIMT started at postoperative day 8 (d8) and lasted for 2 weeks. We utilized 2-[18F]-fluoro-2-deoxy-D-glucose (18F-FDG) micro PET/CT imaging to evaluate glucose metabolism in different brain regions at baseline, before, and after treatment, respectively.
Results: CIMT improved behavioral performance in the ischemic CIMT group. At the end of treatment, the CIMT group showed lower standardized uptake values (SUVs) in the ipsilateral cingulate, motor and somatosensory cortex, respectively; as well as the anterodorsal hippocampus compared to the Control group (1.80% ± 0.10% vs. 1.92% ± 0.08%, 1.32% ± 0.14% vs. 1.48% ± 0.09%, 1.18% ± 0.14% vs. 1.42% ± 0.15%, 1.68% ± 0.09% vs. 1.79% ± 0.06%, P < 0.05). We also observed higher SUVs in the acbcore shell and cortex insular of the contralateral hemisphere compared to the Control group (2.07% group in the acbcore shell and cortex insular of contralateral P < 0.05).
Conclusion: CIMT improved behavioral outcomes in cerebral ischemic rats and this effect can be attributed to increased glucose utilization in the contralateral hemisphere.
Keywords: Constraint-induced movement therapy; cerebral ischemia; glucose metabolism; micro PET.