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 the easiest types of cells to grow in culture. Their durability also makes them amenable to a wide variety of manipulations ranging from studies employing gene transfection to microinjection. There is evidence that fibroblasts in various parts of the body are intrinsically different. Fibroblasts within tissues are exposed to a dynamic mechanical environment, which influences the structure integrity of both healthy and healing soft tissue. Fibroblasts secrete a non-rigid extracellular matrix that is rich in type I and/or type III collagen. Human bladder stromal fibroblasts (HBdSF) also secrete FGF-7, which interact primarily with bladder epithelial cells. FGF-7 secreted by HBdSF is essential for stimulating the formation of a multilayered stratified bladder epithelium. HBdSF from ScienCell Research Laboratories are isolated from human bladder tissue. HBdSF are cryopreserved at passage one and are delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. HBdSF are characterized by immunofluorescence with antibodies specific to fibronectin. HBdSF are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HBdSF are guaranteed to further expand for 15 population doublings under the conditions provided by ScienCell Research Laboratories. Recommended Medium It is recommended to use Fibroblast Medium (FM, Cat. #2301) for the culturing of HBdSF in vitro.