Fibroblasts are mesenchymal cells derived from the embryonic mesoderm. They have been extensively used for a wide range of cellular and molecular studies as they are one of easiest types of cells to grow in culture. Their durability also makes them amenable to a variety of manipulations ranging from studies employing gene transfection to microinjection. In general, fibroblasts secrete a non-rigid extracellular matrix which is rich in type I and/or type III collagen. There is evidence showing that fibroblasts in different organs are intrinsically different. Dermal fibroblasts switch from a proliferative, migratory phase to a contractile, matrix-remodeling phase during wound healing. In addition, they secrete large quantities of hyaluronan in response to inflammatory stimuli. RDF from ScienCell Research Laboratories are isolated from neonatal rat skin. RDF are cryopreserved at P0 and delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. RDF are characterized by their spindle morphology and immunofluorescence with antibody specific to fibronectin. RDF are negative for mycoplasma, bacteria, yeast, and fungi. RDF are guaranteed to further expand for 5 population doublings under the conditions provided by ScienCell Research Laboratories. Recommended Medium It is recommended to use Fibroblast Medium (FM, Cat. #2301) for culturing RDF in vitro.