Morroniside improves microvascular functional integrity of the neurovascular unit after cerebral ischemia.

Treating the vascular elements within the neurovascular unit is essential for protecting and repairing the brain after stroke. Acute injury on endothelial systems results in the disruption of blood-brain barrier (BBB), while post-ischemic angiogenesis plays an important role in delayed functional recovery. Here, we considered alterations in microvessel integrity to be targets for brain recovery, and tested the natural compound morroniside as a therapeutic approach to restore the vascular elements of injured tissue in a rat model of focal cerebral ischemia. Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) model, and morroniside was then administered intragastrically once a day at doses of 30, 90, and 270 mg/kg. BBB integrity and associated factors were analyzed to identify cerebrovascular permeability 3 days after MCAO. The recruitment of endothelial progenitor cells (EPCs), the expression of angiogenic factors and the new vessel formation in the peri-infarct cortex of rats were examined 7 days after MCAO to identify the angiogenesis. We demonstrated that at 3 days post-ischemia, morroniside preserved neurovascular unit function by ameliorating BBB injury. By 7 days post-ischemia, morroniside amplified angiogenesis, in part by enhancing endothelial progenitor cell proliferation and expression of angiogenic factors. Morever, the increase in the amount of vWF+ vessels induced by ischemia could be extended to 28 days after administration of morroniside, indicating the crucial role of morroniside in angiogenesis during the chronic phase. Taken together, our findings suggested that morroniside might offer a novel therapeutic approach for promoting microvascular integrity recovery and provide a thoroughly new direction for stroke therapy.

Promoting neurogenesis via Wnt/ß-catenin signaling pathway accounts for the neurorestorative effects of morroniside against cerebral ischemia injury.

Ischemic stroke is a leading cause of mortality and permanent disability in adults worldwide. Neurogenesis triggered by ischemia in the adult mammalian brain may provide insights into stroke treatment. Morroniside is an active component of sarcocarp of C. officinalis that have shown neuroprotective effects. The aim of the present study is to test whether morroniside promotes neurogenesis via Wnt/ß-catenin signaling pathway for brain recovery in a rat model of focal cerebral ischemia. Morroniside was administered intragastrically once daily at the concentrations of 30, 90 and 270 mg/kg for 7 days post-ischemia. Neurological functions were detected by Ludmila Belayev score tests. Endogenous neural stem cells responses were investigated with immunofluorescence staining of Ki-67 and Nestin to identify the neurogenesis in the subventricular zone (SVZ). The expression of proteins involved in and related to Wnt/ß-catenin signaling pathway was detected by western blotting analysis. Morroniside significantly promoted neurogenesis for brain recovery 7 days post-ischemia. Increased expression of Wnt 3a, ß-catenin and T-cell transcription factor-4 (Tcf-4), along with activation of downstream transcription factors Pax6 and neurogenin2 (Ngn2), indicated that the neurorestorative effects of morroniside may be associated with Wnt/ß-catenin signaling pathway. These data provide support for understanding the mechanisms of morroniside in neurorestorative effects and suggest a potential new strategy for ischemic stroke treatment.