4.6. Caspase 3/7 Assay

The activity of caspase 3 and 7 was measured using a Caspase-Glo 3/7 assay (Promega, Mannheim, Germany), according to the manufacturer’s instructions. 1 × 10⁴ cells were seeded in white 96-well cell culture plates (Greiner Bio-One, Frickenhausen, Germany) in triplicates and were pretreated for 24 h with 1, 10 and 20 μM nimodipine or ethanol alone (solvent control). 24 h after the stress induction with 150 mM NaCl (osmotic stress), 2% EtOH (oxidative stress) or incubated 6 h at 42 °C (heat stress), the cells were incubated for 30 min with 100 μL Caspase-Glo 3/7 reagent in the dark, followed by a measurement of the luminescence signals (Tecan Reader Infinite F200PRO, Tecan, Männedorf, Switzerland). A cell-free culture media served as the background control. Signals of untreated stressed cells were set to 100%. The results showed the means ± SD of three technical replicates.