The macroscopic and microscopic effect of low-frequency whole-body vibration after cerebral ischemia in rats

Abstract

Whole body vibration (WBV) has been applied in stroke patients with uncertain effects on motor and sensory dysfunction, and its effects on neurogenesis have not been studied yet. Here, we intended to explore the effects of daily WBV on neurological behavior, brain structure, and neurogenesis after cerebral ischemia in rats for 4 weeks. Results showed that improvements in weight or comprehensive neurological deficits were not significantly different under WBV or control treatment, and the degrees of brain damage and the numbers of necrotic neurons in the ischemic cortex were similar in two groups. However, WBV markedly improved animals' coordination from 14d to 28d (P < 0.05) and muscle strength of the upper limbs at 21d and 28d (P < 0.05 & P < 0.001) compared with the control group. WBV promoted the increase in the number of bromodeoxyuridine-positive (BrdU⁺) cells at 3d (P < 0.05) and 14d (P < 0.001) and the number of BrdU⁺/nestin⁺ cells at 14d (P < 0.01) after ischemia when compared to the control group. The numbers of BrdU⁺/NeuN⁺ cells at 21d and 28d (P < 0.001) were enhanced by WBV treatment. In addition, WBV significantly promoted the proliferation of astrocytes and their neural processes thickening after 14d. The expression levels of neural markers, such as doublecortin, microtubule-associated protein 2, and glial fibrillary acidic protein, were upregulated in the ipsilateral cortex at different time points. Low-frequency WBV showed inconspicuous improvements in behavioral performance and brain damage after cerebral ischemia, but showed the potential in improving coordination and muscle strength and promoted neurogenesis after long-term exposure.

Keywords: Coordination; Muscle strength; Neurogenesis; Stroke; Whole body vibration.