MMP9 and Cognitive impairment: In a previous study where NBP was tested in CCH animals, NBP could reduce cognitive impairment induced by CCH, but the molecular mechanisms underlying the therapeutic effect were different as the study investigated the therapeutic effects of NBP on downregulation of the amyloid precursor protein Aβ40, MMP-2 and MMP-9 proteins in cortex and hippocampus (Wei et al., 2012).