Buyang Huanwu Decoction regulates neural stem cell behavior in ischemic brain

Abstract

The traditional Chinese medicine Buyang Huanwu Decoction has been shown to improve the neu-rological function of patients with stroke. However, the precise mechanisms underlying its effect remain poorly understood. In this study, we established a rat model of cerebral ischemia by middle cerebral artery occlusion and intragastrically administered 5 g/kg Buyang Huanwu Decoction, once per day, for 1, 7, 14 and 28 days after cerebral ischemia. Immunohistochemical staining revealed a number of cells positive for the neural stem cell marker nestin in the cerebral cortex, the subven-tricular zone and the ipsilateral hippocampal dentate gyrus in rat models of cerebral ischemia. Buyang Huanwu Decoction significantly increased the number of cells positive for 5-bromodeoxyuridine (BrdU), a cell proliferation-related marker, microtubule-associated protein-2, a marker of neuronal differentiation, and growth-associated protein 43, a marker of synaptic plasticity in the ischemic rat cerebral regions. The number of positive cells peaked at 14 and 28 days after intragastric administration of Buyang Huanwu Decoction. These findings suggest that Buyang Huanwu Decoction can promote the proliferation and differentiation of neural stem cells and hance synaptic plasticity in ischemic rat brain tissue.

Keywords: BrdU; Buyang Huanwu Decoction; cerebral cortex; cerebral ischemia; dentate gyrus; differentiation; grants-supported paper; growth-associated protein 43; microtubule-associated protein-2; nestin; neural regeneration; neural stem cells; neuroregeneration; proliferation; subventricular zone; traditional Chinese medicine.

Figure 1

Effects of Buyang Huanwu Decoction (BYHWD) on the proliferation of neural stem cells in the infarct periphery after cerebral ischemia. (A–J) Immunohistochemical staining of nestin-positive cells (red) in the middle cerebral artery occlusion (MCAO) group (cerebral cortex or subventricular zone at 1 day and hippocampus at 7 days) and MCAO + BYHWD group (cerebral cortex or subventricular zone at 1 day and hippocampus at 7 days) after cerebral ischemia (× 200; scale bars: 50 μm). (K) Quantification of nestin-positive cells in the cerebral cortex. ^aP < 0.05, vs. normal group; ^bP < 0.05, vs. MCAO group (mean ± SD; n = 6 rats in each group, Student's t-test).

Figure 2

Effects of Buyang Huanwu Decoction (BYHWD) on the quantity of newly regenerated neurons in the cerebral cortex of rats with cerebral ischemia. (A–L) Immunohistochemical staining of microtubule-associated protein-2 (MAP2)/5-bromodeoxyuridine (BrdU) double-stained cells in the subventricular zone (14 days), hippocampus (7 days) or in the cerebral cortex (7 and 14 days) after cerebral ischemia (× 400; scale bars: 25 μm). (M) Quantification of MAP2/BrdU double-stained cells. ^aP < 0.05, vs. middle cerebral artery occlusion (MCAO) group (mean ± SD; n = 6 rats in each group, Student's t-test).

Figure 3

Effects of Buyang Huanwu Decoction (BYHWD) on expression of growth associated protein-43 (GAP-43) in the cerebral cortex of rats with cerebral ischemia. (A–H) Immunohistochemical staining of GAP-43-positive cells in the cerebral cortex at 1, 7 and 14 days after cerebral ischemia in the middle cerebral artery occlusion (MCAO; C, E, G) and MCAO + BYHWD groups (D, F, H) and in the hippocampus at 14 days after cerebral ischemia in the MCAO (A) and MCAO + BYHWD groups (B) (counterstained with 3-amino-9-ethylcarbazole, × 400; scale bars: 25 μm). (I) Quantification of GAP-43-positive cell expression in the cerebral cortex. ^aP < 0.05, vs. normal group; ^bP < 0.05, vs. MCAO group (mean ± SD; n = six rats in each group per time point, Student's t-test).