Rat Cardiac Fibroblasts (RCF) provided are isolated from Sprague Dawley adult rat heart tissue. RCF are cryopreserved at passage one culture and delivered frozen. The cardiac fibroblasts (CF) are the principal cell type of the heart. They provide structural support for cardiac myocytes and are responsible for extracellular matrix synthesis in the heart during growth and pathophysiological conditions. CF are an important cellular component of myocardial responses to injury and the source of paracrine growth factors. Their proliferation and synthesis of matrix is essential for scar formation at sites of myocardial infarction, cardiac fibrosis, and is often complicated by cardiac hypertrophy. CF culture has been widely used as a model to study the cardiac matrix remodeled by physiological (exercise) and pathological (hypertension) stressors.