2.4. Cardiac fibroblasts collagen synthesis assay

Collagen synthesis of NCFs was measured by a ³H-proline incorporation assay [16]. After 48 h of serum starvation, NCFs were pre-treated for 2 h with or without selective inhibitors prior to stimulation with IGF-1 and the addition of ³H-proline (1 μCi per well). Cells were incubated for 48 h before harvesting, and the levels of ³H-proline incorporation quantified as described previously [16].