Effects of insulin on proliferation of heart cells and its role in induction of cardiac hypertrophy

AIM To study the effects of insulin on proliferation of cardiac myocytes and cardiac fibroblasts and its role in induction of cardiac hypertrophy. METHODS ① The neonatal rat cardiac myocytes and cardiac fibroblasts were cultured and identified with light , electron microscopy and immunocytochemistry respectively. ②After the cells were treated with different concentration of insulin, cell proliferation were measured with cell counting , WST 1 metabolic activity and BrdU enzyme linked immunosorbent assay (ELISA) and cell cycle analysis by flow cytometry. RESULTS ① The cultured heart cells showed the morphology and immunocytochemistry characteristic of myocytes and fibroblasts respectively. ② Cell number, optical density of WST 1 cleavage products,BrdU incorporation and the percentage of S+G 2+M of cardiac fibroblasts increased significantly in the presence of insulin ( P 0 01 or P 0 05). However, the above parameters of cardiac myocytes were not different between insulin treated group and blank control group ( P 0 05). CONCLUSION Insulin can promote proliferation of the cultured cardiac fibroblasts. Therefore it may play an important role in induction of cardiac hypertrophy.