MMP9 and Stroke: Valproic acid and sodium butyrate (class I, IIa and III inhibitor) repressed the nuclear translocation of NFκB subunit p65, mitigate MMP9 activity and restore the BBB integrity after stroke by regulating the expression of tight junction proteins, claudin-5, and ZO-1 (Wang et al., 2011; Park and Sohrabji, 2016).