While the expressions of VEGF and TGF-β were undetectable in the brains of sham-operated rats, marked expressions of VEGF and increasing numbers of TGF-β-positive cells were observed in the border area within the ischemic core at 21 days following administration (i.e., 28 days after cerebral ischemia) (Fig. 4A,B). This evidence concerns the gene TGFB1 and brain ischemia.