In the current study, MMP8 genetic-deficient mice (Apolipoprotein E−/−/MMP8−/− mice), as generated in our previous study [11], and a specific MMP8 inhibitor (MMP8i, CAS 236403-25-1) were employed in this study to establish the causal role of MMP8 in thoracic AD (TAD) and explore the therapeutic potential of MMP8i in treating TAD. The gene discussed is MMP8; the disease is Alzheimer disease.