Oral infection of Porphyromonas gingivalis induces pro-atherogenic change in mice

Objectives: Results of epidemiological studies suggest that periodontal infection may play a role in systemic conditions such as cardiovascular diseases. However, there is no evidence for a causal effect. The aim of the present study was to determine whether oral infection of Porphyromonas gingivalis (P.gingivalis) could induce atherogenic changes in mice.Methods: After pretreatment with antibiotics-containing drinking water for 10 days and subsequent 3-days antibiotic-free period, C57BL/6J mice were infected with live P. gingivalis W83 (10⁹ CFU in 100 µl of PBS with 2% carboxymethylcellulose) orally using feeding needle. Infection was repeated ten times at 3-days intervals. Control mice received the antibiotic pretreatment and then sham infected. After 2days of last infection, the mice were euthanized and tissues and sera were obtained. Alveolar bone resorption was assessed by X-ray micro-CT. Serum hs-CRP and IL-6 were measured by ELISA. Gene expression profiles of aorta and liver were analyzed by DNA micro array and quantitative real-time PCR. Results: The Experimental group demonstrated significantly higher serum hs-CRP and IL-6 compared with the control group in addition to an elevated alveolar bone resorption. Gene expression analysis revealed that periodontal infection up-regulated the expression of several genes involved in the atherogenesis such as CCL2 and CRP in the aorta and the liver, respectively. Furthermore, several genes associated with regulation of blood pressure and insulin resistance were down-regulated. Conclusion: Periodontal infection does affect pro-atherogenic change in various tissues through modulating the gene expression profiles suggesting causal association between periodontitis and systemic diseases.