Effect of local heparanase silencing on vascular leakage. Ears of 5 oxazolone-sensitized BALB/c mice were electroporated with either antiheparanase siRNA pSi2 (filled arrows) or empty pSUPER (empty arrows) vectors, 24 hours prior to induction of DTH reaction by application of oxazolone onto the ears of both sides. Evans blue dye was injected intravenously 16 hours later. Unlike the massive Evans blue extravasation observed in pSUPER-electroporated ears, pSi2 electroporation halted vascular leakage, as visualized by the near absence of extravasated Evans blue dye.