Cell survival in the second window of argon preconditioning (1 h) in either pure cardiomyocytes or fibroblasts. Monocultures of cardiomyocytes and fibroblasts (300,000 cells/ibidi) were treated with 50% argon for 1 h and subjected to 5 h of sublethal hypoxia after 24 h, in the second window of preconditioning. Cells were stained with Hoechst33342 (blue, stains all nuclei), Annexin V (green, stains apoptotic cells), Ethidium homodimer III (red, stains necrotic nuclei). (A) Quantification of (B–D) expressed as % viability (number of necrotic nuclei/all nuclei, normalized to normoxic control cells; (B) cardiomyocytes without argon; (C) cardiomyocytes with argon; (D) fibroblasts without argon; (E) fibroblasts with argon. Data represented means ± SEM of five independent experiments. *, p < 0.05.