MMP9 and Stroke: In the ischemic stroke, Koh et al. reported that PARP-1 inhibitor (3-AB, given at 15 min before MCAO) could reduce ischemic cell death and neuro-inflammatory response,with inflammatory cytokines including CD11b and IL-1β down-regulated in the 3-AB treatment group (Koh et al., 2004).Xu et al. (2016) found that PARP-1 inhibitor (PJ34, given immediately after MCAO and followed by one injection per day until brain harvest at 72 h after injury) could block post-stroke microglial activation and reduce MMP9 level.