Ovarian glycosaminoglycans potentiate angiogenic activity of epidermal growth factor in mice

Epidermal growth factor (EGF) has been shown to induce capillary proliferation. In the course of our investigation on the interaction of ovarian components with EGF, we observed that partially purified glycosaminoglycans (GAGs) isolated from mouse ovaries enhanced the angiogenic activity of EGF when applied simultaneously to the lateral wall of the sheath of musculus rectus abdominis. Mouse EGF from submandibular glands embedded in Elvax 40 implanting on the musculus rectus abdominis induced neovascularization in a dose-dependent manner. When 0.5 micrograms ovarian GAGs was embedded in the implant with a low amount of EGF that induced only slight neovascularization (0.5 or 1 microgram/implant), the angiogenic activity of the growth factor was markedly enhanced. The active GAG component was isolated by chromatography on Dowex 1-x2. The fraction eluted with 0.5 M NaCl possessed the greatest activity to potentiate the angiogenic activity of EGF. When the reaction mixture of GAGs and EGF was treated with 1% cetylpyridinium chloride, the angiogenic activity was identified with the supernatant. On the other hand, after incubating EGF with 0.5 M NaCl fraction, the angiogenic activity of EGF was identified with the precipitate (GAG fraction) of the cetylpyridinium chloride-treated reaction mixtures. These findings show that ovarian GAGs potentiate the angiogenic activity of EGF by interacting or complexing with EGF.