MMP9 and Alzheimer disease: Another important finding in the present study is that the expressions of inflammatory markers including CD68-positive cells, TNF-1α, MMP-9, ICAM-1, and NF-κB were notably higher in NP-treated animals (group 2), and further increased in the AD-treated group (group 3), and highest in the AD-NP-treated group (group 4) compared with those in the normal controls (group 1).