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An Ex Vivo Platform for Studying Angiogenesis in Perfused Microvascular Networks

A challenge in tissue engineering biomimetic models for studying angiogenesis is building the physiological complexity of real microvascular networks. Utilizing an alternative top‐down approach, our laboratory recently introduced the rat mesentery culture model as an ex vivo experimental platform for investigating the multi‐cellular dynamics involved in angiogenesis within an intact microvascular network. However, a current limitation of the model is that microvessels are not perfused. The objective of this study was to demonstrate the feasibility of perfusing microvascular networks during the culture of rat mesentery tissue. Adult Wistar rat mesentery tissues were harvested along with a feeding second order arteriole and venule, and then transferred to a customized tissue chamber for perfusion. The arteriole was cannulated with a glass pipette (40 – 60 μm diameter) and secured in place with 7–0 suture. Injection with blue food dye through the cannulated arteriole identified the lumens of vessels across the hierarchy of intact microvascular networks and confirmed successful perfusion. Tissues with cannulated arterioles were cultured in the perfusion chamber up to three days with either minimum essential media (MEM) or MEM supplemented with 10% serum. Live/dead labeling confirmed that cannulated mesentery tissues remain viable after three days in culture. Additional labeling with BSI‐lectin identified endothelial cells along microvascular networks and confirmed the tissues were undergoing angiogenesis, characterized by increases in vascular density and capillary sprouting. These results demonstrate the ability to perfuse intact microvascular networks ex vivo in cultured mesentery tissues and supports the novelty of the rat mesentery culture model as a biomimetic tool for investigating angiogenesis.