HDAC and HAT activity assay.

Total HDAC and HAT activities were measured in nuclear extracts prepared from the heart tissues. HAT and HDAC activities were determined with a colorimetric ELISA assay kit (EpiQuik HDAC or HAT activity/inhibition kit). Absorbance was read at 450 nm, and activities were calculated using a standard curve for HDAC (ng·min⁻¹·mg protein⁻¹) and HAT (ng·h⁻¹·mg protein⁻¹) as per manufacturer's instructions.