Microbial profile of ligature-induced periodontitis in rats

Objective

The aim of this study was to evaluate the composition of the biofilm accumulated around ligatures in rats by checkerboard DNA-DNA hybridization using probes made from human oral bacterial species.

Methods

12 Wistar rats were selected for this study. One of the mandibular first molars of each animal received a ligature, while the contralateral tooth was left unligated to be used as a control. Forty-two days later, the ligatures and one sample of biofilm from each unligated teeth were analyzed by checkerboard DNA-DNA hybridization for 40 human periodontal species. The area of bone loss in the furcation area was determined histometrically.

Results

The unligated teeth did not present any of the bacterial species tested. Twenty five species were detected in the ligatures. Streptococcus- and Actinomyces-like species were found in high mean counts, followed by Fusobacterium-, Prevotella nigrescens- and Parvimonas micra-like species and Porphyromonas gingivalis- and Aggregatibacter actinomycetemcomitans-like species. Greater bone loss was observed in the furcation area of the ligated than of the unligated group (p < 0.0001).

Conclusion

At 42 days, the ligature biofilm in rats presents various bacterial species that hybridize to probes of periodontal bacterial species commonly observed in human.