Increased cortical infarction and neuroinflammation in ischemic stroke mice with experimental periodontitis

Ischemic stroke is a common life-threatening disease. Epidemiological studies have shown that chronic periodontitis is closely related to ischemic stroke. However, it remains unknown whether periodontitis plays a direct role in the injury of cerebral ischemia. To explore the role of chronic periodontitis in the development process of ischemic stroke, we combined two mouse models: experimental periodontitis induced by a periodontal injection of lipopolysaccharide and ischemic stroke induced by the photothrombotic method. Alveolar bone loss and inflammatory infiltration of the periodontal tissue were found in the mice with experimental periodontitis. Periodontitis significantly increased the infarction volume, and numbers of activated microglia and astrocytes. Furthermore, an increased expression of nod-like receptor protein 3 inflammasome and interleukin-1β was detected in the peri-infarct region. We drew a conclusion that chronic periodontitis exacerbated ischemic stroke by increasing the activation of microglia/astrocytes and the expression of nod-like receptor protein 3 inflammasome and interleukin-1β. This suggested that chronic periodontitis played a role in ischemic brain injury directly through exacerbating the inflammation of the damaged brain.