Effects of MSCs on angiogenesis. Rats with MCAO received intra-carotid infusion of 1 million monolayer or 3D spheroid hMSCs or equal volume of vehicle PBS 24 h after MCAO. Tissue sections of the brain at 3 days were immunostained for Von Willebrand factor (vWF) [(A), green], and tissue sections at 7 days were immunostained for α-smooth muscle actin (α-SMA) [(B), red], which were subjected to examination under confocal microscope. The total area of vessels per macroscopic field area in the infarct boundary zone was measured [(C), n=5, *P<0.05; **P<0.01]. Nuclei were stained with 4′,6-diamidino-2-phenylindole (blue). Color images available online at www.liebertpub.com/scd