gingivalis</i> successfully induced periodontitis in mice and led to EndoMT in the hippocampus, characterized by downregulation of ZO-1 and Claudin-5 and upregulation of <i>α</i>-SMA, along with inflammatory activation evidenced by elevated levels of iNOS, IL-1β mRNA, and IL-6 mRNA. The gene discussed is CLDN5; the disease is periodontitis.