Modulatory role of exogenous arachidonic acid in periodontitis with type 2 diabetes mellitus mice.

Background: Type 2 diabetes mellitus (T2DM) exhibits a bidirectional relationship with periodontitis, wherein each condition influences the progression of the other. Arachidonic acid (AA) exerts an anti-diabetic effect, while showing a protective effect by regulating the inflammatory response independently of its metabolites. However, its impact on periodontitis with T2DM remains poorly understood.

Methods: The T2DM mouse model was established by combining a high-sugar and high-fat diet with streptozotocin injection, followed by silk ligation to induce periodontitis. Alterations in diabetes-associated symptoms were evaluated. Micro-computed tomography was used to measure bone-related parameters, including the distance from the cementoenamel junction to the alveolar bone crest, bone volume/total volume and bone mineral density. Targeted metabolomics analysis was conducted to evaluate the impact of exogenous AA on serum metabolite levels of AA in mice with type 2 diabetic periodontitis. 16S rRNA gene sequencing was utilized to analyze the microbial diversity. The activity of osteoclasts, levels of inflammatory factors and gene expression related to osteoclasts were investigated using TRAP staining and real-time quantitative PCR.

Results: The periodontitis mouse model with T2DM was successfully established. Following two weeks of exogenous AA treatment, a reduction in fasting blood glucose levels was observed in the diabetic periodontitis mice. Exogenous AA alleviated alveolar bone loss in type 2 diabetic periodontitis mice. However, it had no substantial effect on the contents of serum AA-targeted metabolites. Exogenous AA reduced Staphylococcus in subgingival flora of type 2 diabetic periodontitis mice, but had no significant impact on microbial community structure or diversity. Furthermore, it decreased the number of osteoclasts in the alveolar bone of periodontitis with T2DM mice and increased IL-10 mRNA expression in its gingival tissue.

Conclusion: Exogenous AA may alleviate alveolar bone loss in T2DM mice with periodontitis by reducing the number of osteoclasts and increasing the expression of IL-10 mRNA in periodontal tissues, rather than the change of AA-targeted metabolites in serum or the composition and diversity of microorganisms in subgingival plaque. These findings may provide a potential therapeutic approach for the prevention and treatment of periodontitis with T2DM.