Culture of primary BM ECs
As previously reported [23-27], BMMNCs were extracted and seeded to the cell culture plates (Corning, NY, USA) pre-coated with fibronectin (Sigma, MO, USA). EGM-2-BulletKit (Lonza, MD, USA) medium with extra 10% foetal bovine serum (FBS) (Gibco, MA, USA) was added to the cell plates and was renewed on the fourth day to supplement nutrition for cells.