For example, in vitro, 0.1 μM minocycline has been shown to inhibit the apoptosis promoting enzyme activity of poly (ADP-ribose) polymerase 1 (PARP-1) and confer 85% increased survival of neurons in culture, and 5 mg/kg intraperitoneal minocycline delayed cell death and inhibited caspase-1 and caspase-3 expression in the brains of a mouse model of Huntington's disease [49]. This evidence concerns the gene PARP1 and Huntington disease.