Atrial fibroblast isolation.
Primary cultures of rat atrial fibroblasts were isolated from the hearts of middle-aged Sprague-Dawley rats (6 months old, Charles River Laboratories) using enzymatic digestion (Collagenase Type II, Worthington Biochemical) at 37°C. Cells were cultured in Dulbecco’s Modified Eagle High Glucose Medium (Thermo Fisher Scientific), supplemented with 10% fetal bovine serum (Thermo Fisher Scientific), 1% 