In ovo technique for cell injection in the CPM followed by bead implantation in the BA2 of chicken embryos

The major advantage of chicken embryos model is their accessibility for microsurgical manipulations and the dissection of tissues for ex vivo explant culture. Branchial arches are embryonic structure located next to the top of developing heart. Each arch is made of surface ectoderm, endoderm, myogenic mesoderm cells and cranial neural crest cells. The myogenic mesoderm originates from cranial paraxial mesoderm (CPM), which is transiently migrated to branchial arches (BAs). The first branchial arch (BA1) mesoderm contributes to formation of mastication muscles. The second branchial arch (BA2) mesoderm gives rise to facial expression muscles. This article focuses on cell injection in the CPM and bead implantation (gain of function approaches) in the BA2. In order to follow the migration of mesoderm progenitor cells from CPM to BA2, we injected quail cells in the CPM of stage HH10-11 embryos, followed by implantation of SDF-1 bead at stage HH15-16. Later the attraction of quail cells (CXCR4(+)) towards the SDF-1 source has been observed, using whole-mount immunostaining of a specific quail antibody (QCPN) at stage HH19-22. • Our method, which involves bead implantation followed by quail cell injection, provides useful tools for tracing migratory mesodermal cells in vivo. • The proposed method does not require any commercial kits and can be used for various developmental process. • It does not employ any complicated methods such as genetically engineered permanent cell labeling, multiplicity of fluorescent markers or clonal analysis.