Mouse maternal odontogenic infection with Porphyromonas gingivalis induces cognitive decline in offspring

Introduction Porphyromonas gingivalis (P. gingivalis), a major periodontal pathogen, causes intrauterine infection/inflammation. Offspring exposed to intrauterine infection/inflammation have an increased risk of neurological disorders, regardless of gestational age. However, the relationship between maternal periodontitis and offspring functional/histological changes in the brain has not yet been elucidated.Methods In this study, we used a gestational mouse model to investigate the effects of maternal odontogenic infection of P. gingivalis on offspring behavior and brain tissue.Results The step-through passive avoidance test showed that the latency of the acquisition trial was significantly shorter in the P. gingivalis group (p < 0.05), but no difference in spontaneous motor/exploratory parameters by open-field test. P. gingivalis was diffusely distributed throughout the brain, especially in the hippocampus. In the hippocampus and amygdala, the numbers of neuron cells and cyclic adenosine monophosphate response element binding protein-positive cells were significantly reduced (p < 0.05), whereas the number of ionized calcium binding adapter protein 1-positive microglia was significantly increased (p < 0.05). In the hippocampus, the number of glial fibrillary acidic protein-positive astrocytes was also significantly increased (p < 0.05).Discussion The offspring of P. gingivalis-infected mothers have reduced cognitive function. Neurodegeneration/neuroinflammation in the hippocampus and amygdala may be caused by P. gingivalis infection, which is maternally transmitted. The importance of eliminating maternal P. gingivalis-odontogenic infection before or during gestation in maintenance healthy brain function in offspring should be addressed in near future.

Automated summary

This study investigated the effects of maternal odontogenic infection of P. gingivalis on offspring behavior and brain tissue using a gestational mouse model. The results showed that the offspring of infected mothers had reduced cognitive function but no difference in motor/exploratory parameters. P. gingivalis was widely distributed in the brain, especially in the hippocampus. Neurodegeneration/neuroinflammation in the hippocampus and amygdala may be caused by maternally transmitted P. gingivalis infection. The importance of eliminating maternal P. gingivalis-odontogenic infection for maintaining healthy brain function in offspring should be addressed in the future.