Pericardial fluid (PF) is located in the space between the heart and the pericardium surrounding the heart. PF contains mesothelial cells and leukocytes such as monocytes, lymphocytes, macrophages, and neutrophils. Mesothelial cells are similar to mesenchymal stem cells with their differentiation potential and characteristic features. The number of mesothelial cells not only increases with damage to the heart, but also secrete growth factors to support tissue repair. In this study, 1, 10, 20, 50 ng/mL vascular endothelial growth factor (VEGF) was added to the in vitro cultured cells isolated from bovine pericardial fluid.