Morroniside promotes angiogenesis and further improves microvascular circulation after focal cerebral ischemia/reperfusion

• Morroniside promotes angiogenesis after focal cerebral ischemia/reperfusion.
• Newly generated vessels enhances rCBF and improves microvascular circulation.
• Angiogenic effect of morroniside is mediated by the ephrinB2/VEGFR2 signaling.
• Morroniside eventually reduces the infarct volume and improves functional recovery.

Preservation of cerebral microvascular functional integrity is crucial for protecting and repairing the brain after stroke. Our previous study demonstrated that morroniside promoted angiogenesis 7 days after stroke. The current study aimed to further evaluate the long-term effects of morroniside on angiogenesis and to examine whether angiogenesis induced by morroniside could improve blood flow velocity. Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO), and morroniside was then administered once per day at a dose of 270 mg/kg. New vessel formation and the expression of ephrinB2/VEGFR2 signaling pathway components were examined 14 days after MCAO to examine angiogenesis and the associated mechanisms. The dynamics of regional cerebral blood flow (rCBF) and the number of vessels of the leptomeningeal anastomoses were analyzed to characterize microvascular circulation 3 days after MCAO. We demonstrated that morroniside promoted angiogenesis by regulating the ephrinB2/VEGFR2 signaling pathway 14 days post-ischemia. By 3 days post-ischemia, morroniside improved rCBF and increased the number of vessels of the leptomeningeal anastomoses. Moreover, morroniside decreased the infarct volume and improved neurological function 14 days after MCAO. Our findings suggest that morroniside promoted long-term angiogenesis, thereby improving microvascular circulation and neurological function. It suggested that the angiogenic mechanism of morroniside might be mediated by the ephrinB2/VEGFR2 signaling pathway.