In order to better understand how exercise affects motor pathway and improves motor functions after stroke, we evaluated the effects of exercise on the balance of glucose metabolism between hemispheres in cerebral ischemic rat model.

Adult male Sprague Dawley rats were divided into a sham-operated group (sham group, n=6), an ischemic group without exercise (control group, n=3), and an ischemic group treated with wheeling (exercise group, n=5). Cerebral ischemia was established using the middle cerebral artery occlusion (MCAO) procedure (Day 0). An exercise wheel was started from Day 3. The speed was set at 1rpm, gradually increased to 4–5rpm as tolerated, lasting 20min per day till Day 28. Micro-PET/CT imaging with ¹⁸F-FDG was used to evaluate glucose metabolism of brain areas related to motor functions, including motor cortex, caudate putamen, midbrain and pars compacta, at Day 28. The results presented as standardized uptake values (SUV), then normalized with the SUV of the cerebellum. In order to compare the balance of glucose metabolism between hemispheres, we used the ratio of the left side over the right side in respective areas. One-way ANOVA or Kruskal–Wallis test were used for comparison. P<0.05 indicated statistical significance.

The average ratio in the sham group was largely close to 1, indicating natural balance of glucose metabolism between hemispheres (Table 1). There was significant imbalance of glucose metabolism in the motor pathways between hemispheres in the control group, with the glucose metabolisms on the left side being 50%–70% of the right side. However, these imbalances were milder in the exercise group, with the left being 70%–100% of the right, closer to the sham group (Fig. 1).

Exercise may contribute to bring balance of glucose metabolism to bilateral motor pathway in cerebral ischemic rat.