BALB/c Mouse Primary Cardiac Fibroblasts from Creative Bioarray are isolated from tissue of pathogen-free laboratory mice. Mouse Primary Cardiac Fibroblasts are grown in T25 tissue culture flasks pre-coated with gelatin-based solution for 0.5 hour and incubated in Creative Bioarray Culture Complete Growth Medium generally for 3-7 days. Cultures are then expanded. Prior to shipping, cells are detached from flasks and immediately cryo-preserved in vials. Each vial contains at least 1x10^6 cells per ml and is delivered frozen. Mouse Primary Cardiac Fibroblasts are negative for bacteria, yeast, fungi, and mycoplasma. Cells are tested for expression of marker using the antibody of anti-FSP1/S100A4 by immunofluorescence staining. Cells can be expanded for 2-5 passages at a split ratio of 1:2 under the cell culture conditions specified by Creative Bioarray. Repeated freezing and thawing of cells is not recommended. Standard biochemical procedures performed with cell cultures include the assay of cell to cell interaction, RT-PCR, Western blotting, immunoprecipitation, immunofluorescent staining, flow cytometry or generating cell derivatives for desired research applications.