LAUSR

Guanosine (GUO) is neuroprotective when administered acutely for the treatment of cerebral ischemia. The aim of the present study was to investigate whether delayed administration of GUO improved long-term functional recovery following stroke, as well as to explore the potential underlying mechanisms. GUO (8 mg/kg) or a vehicle was administered intraperitoneally for 7 consecutive days beginning 24 h prior to photothrombosis-induced stroke in male C57/B6J mice. Behaviour tests were performed at days 1, 3, 7, 14 and 28 post-stroke. Infarct volume was measured using Nissl staining at day 7 post-stroke. Neurogenesis and angiogenesis were evaluated by co-labelling bromodeoxyuridine (BrdU) with doublecortin (DCX), neuronal nuclei (NeuN) and von Willebrand factor, in immunohistochemical studies. Brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) levels in the ipsilesional brain at day 28 post-stroke were detected by western blot analysis. Delayed administration of GUO did not reduce infarct volume or affect neurological function at day 7 post-stroke; however, it did improve functional recovery from day 14 post-stroke, when compared with the vehicle group. GUO significantly increased the number of BrdU+ and BrdU+/DCX+ cells in the subventricular zone and subgranular zone at all examined time points, the number of Brdu+/NeuN+ cells in the peri-infarction region at days 14 and 28 post-stroke and microvessel density in the peri-infarction region at day 28 post-stroke compared with the vehicle group. In addition, the BDNF and VEGF levels in the ipsilesional brain were significantly elevated. Delayed administration of GUO at 24 h post-stroke enhanced neurogenesis and angiogenesis, and increased BDNF and VEGF levels, which likely contributes to long-term functional recovery following stroke.