Sclerotomal Differentiation of Somitic Cells Co-Cultured with Chicken Embryonic Notochord

The somites are epithelial blocks of mesodermal cells differentiating to sclerotome and dermomyotome and notochord or axial mesoderm plays a major role in somitic cell differentiation to sclerotome. This study was aimed to evaluate the role of the notochord in sclerotomal differentiation of the somites in vitro. In this experimental study, isolated notochords from chick embryo were encapsulated in alginate beads and co-cultured with somites for six days. In control group, the somites were cultured alone. Newly isolated and non-cultured somites were considered as somites on day 0. Eventually, morphology of cultured somitic cells was evaluated by inverted microscope and then RT-PCR method was used to analyze the sclerotomal and dermomyotomal gene expression profile. In comparison with control group, the somitic cells co-cultured with notochord had highly differentiation potential and showed mesenchymal morphology with numerous slender processes. Gene expression profile of co-cultured somitic cells indicated upregulation of Pax1 and BMP4 and downregulation of MyoD, presenting sclerotomal cell characteristics. Embryonic notochord can induce in vitro sclerotomal differentiation in somites through upregulation of genes involving in this differentiation.