Evaluation of tissue levels of Toll-like receptors and cytokine mRNAs associated with bovine periodontitis and oral health

Bovine periodontitis is a progressive and purulent infection associated with an anaerobic subgingival biofilm, which induces irreversible damage to the dentition of affected animals. The aetiopathogenesis of the disease is unclear and treatment and control of the disease process in cattle are almost unknown. The aim of this study was to investigate the innate immune response by quantifying expression of Toll-like receptor (TLR) and cytokine genes in gingival tissue samples from cattle with and without periodontitis. Postmortem biopsies of gingival tissues were collected from 20 cattle with periodontitis and 20 cattle with no clinical signs of periodontal lesions. Tissue expression of TLR2, TLR4, TNF-α, IFN-γ, IL-1β and IL-4 genes were determined using quantitative real-time PCR. Statistically significant increases in mRNA levels encoding TLR2 (p = 0.025), TLR4 (p = 0.037), TNF-α (p = 0.025), IFN-γ (p = 0.014), IL-1β (p < 0.001) and IL-4 (p = 0.014) were observed in animals with periodontitis when compared to periodontally healthy animals. Increased levels of TLRs and inflammatory cytokines in periodontal tissue indicate an induction of the innate immune response of cattle and suggest that a substantial microbial challenge may be involved in the aetiopathogenesis of bovine periodontitis.