HIF1A and ischemia: Many studies have shown that upregulation of HIF-1α can be induced by overexpression of VEGF in ischemic brain injury, which can, on the one hand, alleviate brain injury after ischemia by promoting the proliferation and migration of microvascular endothelial cells (MECs), increasing angiogenesis, improving local blood supply, and protecting endothelial cells from degeneration and necrosis, while at the same time protecting neurons by directly or indirectly inhibiting neuronal apoptosis [50–52].