Metformin promotes focal angiogenesis and neurogenesis in mice following middle cerebral artery occlusion

- Metformin alleviates brain atrophy volume.
- Metformin promotes focal angiogenesis and neurogenesis.
- The protective effect of metformin is via activating AMPK-eNOS pathway.

Current studies demonstrated that metformin is not only a hypoglycemic drug, but also a neuro-protective agent. However, the effect of metformin during ischemic brain injury is unclear. The aim of the present study is to explore the effect of metformin during ischemic brain injury. Adult male CD1 mice underwent 90 min transient middle cerebral artery occlusion. Metformin (200 mg/kg) was given at the time of reperfusion daily until sacrifice. Results showed that metformin treatment significantly reduced ischemia-induced brain atrophy volume compared to the control (p < 0.05). Immunostaining results showed that the microvessel density in the peri-focal region of metformin treated mice was greatly increased compared to the control (p < 0.05). Similarly, the numbers of BrdU+/DCX+ and nestin+ cells in the subventricular zone were increased in metformin treated mice compared to the control (p < 0.05). Furthermore, we demonstrated that metformin treatment activated AMPK signaling pathway and promoted eNOS phosphorylation. Thus, we concluded that metformin promoted focal angiogenesis and neurogenesis and attenuated ischemia-induced brain injury in mice after middle cerebral artery occlusion, suggesting that metformin is a potential new drug for ischemic stroke therapy.