Accelerated alveolar bone loss in HLA-b27 transgenic rats: An adult onset condition

OBJECTIVE: Patients with arthritis and Crohn's disease may be more susceptible to periodontitis associated alveolar bone loss (ABL). HLA-B27 transgenic (TG) rats spontaneously develop arthritis and colitis. Based on the hypothesis that TG rats would also be susceptible to ABL, we compared the naturally occurring ABL in TG and Fischer 344 wild-type (WT) rats.

METHODS: Eighteen TG and 18 WT virgin female rats were used. Pairs (I TG, I WT) were housed in suspended wire cages. At age 2.6, 6, and 11 months, 8, 5, and 5 pairs were sacrificed, respectively. ABL was measured as exposed molar root surface area (mm2). Western blotting was used for analysis of serum reactivity against bacteria associated with arthritis, colitis, and periodontitis development.

RESULTS: At 2.6 months of age, there was no difference in ABL between TG and WT rats. At 6 and 11 months ABL was significantly greater in TG animals by 28% and 53%, respectively. For TG rats, ABL was significantly different between the 3 age groups. For WT rats, ABL was not significantly different between 6 and 11 months. Western blotting revealed distinct TG serum reactivity against extracts of Bacteroides vulgatus, B. fragilis, Prevotella intermedia, and to a lesser extent against extracts of B. forsythus.

CONCLUSION: The accelerated ABL in HLA-B27 TG rats is an adult onset condition, independent of husbandry conditions or parity status. HLA-B27 rats exhibit strong immunoreactivity against bacteria implicated in arthritis, colitis, and periodontitis.