ChronicPorphyromonas gingivalisinfection accelerates the occurrence of age-related granules in ApoE-/-mice brains.
This study explored the origin of age-related granules in the apolipoprotein E gene knockout (ApoE-/-) B6 background mice brains following chronic gingival infection withPorphyromonas gingivalisfor 24 weeks. Intracerebral localization ofP. gingivaliswas detected by fluorescencein situhybridization (FISH) and its protease by immunohistochemistry. The age-related granules were observed by periodic acid-Schiff (PAS), silver impregnation, and immunostaining. FISH showed intracerebral dissemination ofP. gingivaliscells (p= 0.001). PAS and silver impregnation demonstrated the presence of larger inclusions restricted to the CA1, CA2, and dentate gyrus sectors of the hippocampus. A specific monoclonal antibody to bacterial peptidoglycan detected clusters of granules with variable sizes in mice brains infected withP. gingivalis(p= 0.004), and also highlighted areas of diffuse punctate staining equating to physical tissue damage. Mouse immunoglobulin G was observed in the capillaries of the cerebral parenchyma of allP. gingivalis-infected brains (p= 0.001), and on pyramidal neurons in some severely affected mice, compared with the sham-infected mice. Gingipains was also observed in microvessels of the hippocampus in the infected mice. This study supports the possibility of early appearance of age-related granules in ApoE-/-mice following inflammation-mediated tissue injury, accompanied by loss of cerebral blood-brain barrier integrity.
Dementia and Neurodegeneration Research Group, College of Clinical and Biomedical Sciences, University of Central Lancashire , Preston , UK.
Sim K
SK
Singhrao
Department of Periodontology, University of Florida , Gainesville , FL , USA.
Sasanka
S
Chukkapalli
Dementia and Neurodegeneration Research Group, College of Clinical and Biomedical Sciences, University of Central Lancashire , Preston , UK.
Sophie
S
Poole
Department of Periodontology, University of Florida , Gainesville , FL , USA.
Irina
I
Velsko
Dementia and Neurodegeneration Research Group, College of Clinical and Biomedical Sciences, University of Central Lancashire , Preston , UK.
St John
SJ
Crean
Department of Periodontology, University of Florida, Gainesville, FL, USA; Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA.
Lakshmyya
L
Kesavalu
Age-related granules; blood–brain barrier damage; infection; inflammation; injury