The effect of HDAC inhibitor Trichostatin A (TSA) on apoptosis in J774.2 macrophages during culture for 24 h. For comparison, is shown the effect of a known inducer of apoptosis in J774 macrophages, i.e. combination of LPS (10 ng/ml) and PDTC (100 μM). Apoptosis was assessed by flow cytometry measuring the percentage of Annexin V-positive cells. *P < 0.05 and **P < 0.01 as compared with the respective control. Mean ± S.E.M., n = 12.