The fetal mouse metatarsal bone explant as a model of angiogenesis

Abstract

The mouse fetal metatarsal provides a unique tool for studying angiogenesis. In comparison with other commonly used in vitro or ex vivo angiogenesis assays, vessel outgrowth from mouse fetal metatarsals is more representative of sprouting angiogensis in vivo. It allows the analysis of blood vessel growth, and the mechanisms underpinning this process, in a multicellular microenvironment that drives the formation of a robust and complex vascular network in the absence of exogenous growth factors. By labeling different constituents of the vascular structure, it is possible to perform 3D rendering of the spatial interplay between different cellular components and to carry out quantitative analysis of vessel outgrowth. High-resolution imaging permits the visualization of fine structural and cellular details. As the assay involves the use of fetal tissues, it is possible to follow new blood vessel formation in genetically modified mice that are perinatally lethal. The entire process takes 9-13 d. A detailed description of how to set up and perform the assay is described here.

Angiogenesis Assays for the Evaluation of Angiogenic Properties of Orthopaedic Biomaterials – A General Review

“…Without exogenous angiogenic factors, the vessel outgrowth of aortic ring is limited making it less favorable in some research situations . This organ culture system with metatarsal is a complex in vivo mimicry with multiple cell types consisting ECs, mural cells, fibroblasts, macrophages and bone cells, etc . Metatarsals of 17‐day‐old mice are dissected from both feet while three metatarsals can be collected from each foot excluding the big and small toes.…”

“…After 5–6 days of culture, a resorption cavity is formed in the middle and expends gradually due to the presence of osteoclasts in the bone. Images of the vessel outgrown from the metatarsals can be taken throughout the entire culture period using optical microscope or fluorescent microscope with immunofluorescence staining using specific markers for further analysis . In addition, the RNA or protein expression of the metatarsal bone and the outgrowing cells can also be analyzed in this system.…”

Beyond organoids: In vitro vasculogenesis and angiogenesis using cells from mammals and zebrafish

“…Various tissue explants have been shown to have the ability to develop vascular sprouts in vitro (Table 4). Examples include cross sections of aorta called aortic rings [161]; metatarsal bones [162]; retina fragments [163]; choroid-sclera fragments [164]; and adipose tissue [165]. In most cases, the tissues for explant preparation are isolated from developing rodent embryos or neonates.…”

Modeling the Human Bone–Tumor Niche: Reducing and Replacing the Need for Animal Data

“…However, the use of primary bone tissue in such experiments offers a direct way of sampling the skeletal milieu and where the introduction of new or metastasizing cell types can be easily achieved. ex vivo assays using fresh bone such as fetal rat long bones, (33) mouse calvariae, (34,35) or embryonic metatarsals, (36) have previously been used successfully to investigate cell-specific and heterogeneous populations to test potential bone anabolic agents or to study vascular differentiation and growth. Previous attempts to model the tumor-bone niche using fresh bone tissue have employed murine calvariae dissected from postnatal mice (up to 7 days).…”