FIG. 5.

Intravenous MSCs inhibit angiogenesis in vivo in a matrigel plug assay. (A) Schematic showing experimental set up of the plug assay. Briefly, matrigel plugs without basic fibroblast growth factor (bFGF) (control) or with bFGF (rest) were implanted subcutaneously into C57bl mice and harvested after 7 days. (B) Shows representative photomicrographs of matrigel plugs after Masson's Trichrome staining. Compared with matrigel alone (top left panel), bFGF induces potent angiogenesis in matrigel plugs (top right panel). Coinjecting 1×10⁶ MSCs within the matrigel plugs at the time of implantation had no effect on vessel formation (bottom left panel). However, administration of 2 dosages (1×10⁶ MSCs) via tail vein injection markedly reduced vessel formation (bottom right panel). (C) Shows quantification of vessels/high-power field (HPF) from each of the treatment groups shown in (B) (n=3 mice for control, 4 for all other groups). Staining with an antibody against vWF was used to identify blood vessels for quantification. Formaldehyde fixed paraffin-embedded sections were immunostained with monoclonal Factor VIII antibody as described in Materials and Methods section. Areas of neoangiogenesis were then examined under higher magnification (200×) and counted as described in Materials and Methods section. 32 high-powered fields were counted for each sample. * indicates p<0.05. Color images available online at www.liebertpub.com/scd