A Novel in Vivo Angiogenesis Mouse Model

Purpose: To establish a reproducable, functional and fully vascularized angiogenesis model in mice for subsequent evaluation of leaky vessels associated with neovascularization. Materials and Methods: A biocompatible Poly-Capro-Lactone (PCL) scaffold was implanted subcutaneously in mice, and the development and progression of angiogenesis was evaluated up to 6 weeks after implantation. Mice were euthanized, sponges immersion fixed and paraffinembedded, and HE stained sections prepared for microscopic evaluation. Figure: Representative slides showing how new microvessels (angiogenesis) develop and progressively penetrate through the scaffold. The skin of the mouse is included for orientation. Results: Very little angiogenesis was seen within the scaffold after 1 week. During the subsequent weeks, the scaffold became progressively occupied by microvessel-containing new tissue. No or very limited extravasation of erythrocytes was seen. Within 5–6 weeks the implant was fully vascularized. Conclusion perspectives: We have developed a functional angiogenesis model capable of fully vascularizing the implant within 6 weeks. Histologic examination reveals few if any intra-implant hemorrhages, but Dynamic Contrast Enhanced (DCE)-MRI will elucidate if there are leaky vessels present in the scaffold. High resolution MRI and vessel density will also be assessed to fully characterize this model.