Host-DNA-Fragments in Periodontal Pockets before and after Periodontal Treatment

It is well recognized that host DNA was released from damaged cells into gingival crevice fluid (GCF) and gradually degraded to fragments. In our previous study, 2kbp amplicon of human b globin has been detected more (p< 0.005) in periodontitis group than in gingivitis group, and not detected in healthy group. Objectives: In the present study we aim to elucidate the relationship between the detection of host DNA fragments and host cell damages/periodontal inflammatory conditions. Methods: GCF with chronic periodontitis (n=15) having probing depth>5 mm was collected before and a month after professional clean-up of periodontal pockets as initial phase of periodontal treatment. In addition, GCF was also collected from 10 periodontal pockets just before periodontal surgery (inflammation: resting) and 1 day after (inflammation: iatrogenic acute onsets). GCF was centrifuged at 3,000xg to remove off host cells and furthermore at 13,000xg, and then the pellet and the supernatant was investigated for host-DNA by qualitative polymerase chain reaction (PCR) with specific primers to amplify 536bp and 2kbp of b globin gene. In addition quantitative PCR was carried with primers set of human b globin (Roche). Results: Initial phase of periodontal treatment resulted in significantly reduced detection (p<0.005) of 536bp amplicon (from 100% to 47%) and 2kbp amplicon (from 87% to 0.00%). The copy numbers of globin gene were also reduced from 168 to 45 copies/µl (p<0.05). In contrast, 1 day after surgical procedures, the detection was increased from 50% to 100% for 536bp and 0% to 90% for 2kbp, p<0.005), and the globin gene copies increased also from 27 to 92 copies/µl (p<0.05). Conclusion: The detection of 2kbp amplicon may relate more to host cell-damages and periodontal inflammation than 536bp amplicon, in agreement with our previous results mentioned above. This study was supported by RONPAKU program, JSPS.