CASP3 and atrial fibrillation: After transfection with PRODH siRNA, the levels of Bax and cleaved Caspase-3 in the control/ AFB1/ AFM1 groups were markedly lower (p < 0.05) than in the normal cells, however, the levels of Bax and cleaved Caspase-3 in AFs + l-proline groups were significantly higher than the AF groups (p < 0.05) (Figure 5B).