Therapeutic Potential of Liraglutide for Diabetes-Periodontitis Comorbidity: Killing Two Birds with One Stone

Background. The relationship between diabetes and periodontitis is bidirectional, and there is now consensus that periodontitis and diabetes are comorbid. There is a quest for a drug that can be used to treat both conditions simultaneously. This study evaluated the anti-inflammatory and osteoprotective effects of liraglutide (LIRA) on periodontitis in diabetic rats. Methods. Male Wistar rats (n=46) were randomly divided into four groups: control group (n=8), LIRA group (n=8), diabetes-associated periodontitis+0.9% saline group (diabetic periodontitis (DP)+NaCl group, n=15), and diabetes-associated periodontitis+LIRA group (DP+LIRA group, n=15). LIRA treatment lasted for 4 weeks (300 mu g/kg/d) after establishment of a rat model of DP. The expression of IL-6, TNF-alpha, and IL-1 beta was detected by enzyme-linked immunosorbent assay. The morphological changes of periodontal tissues were observed by hematoxylin-eosin staining. The absorption of alveolar bone and its ultrastructural changes were observed by histomorphometry and microcomputed tomography. The expression of receptor activator of NF-kappa B ligand (RANKL) and osteoprotegerin (OPG) in alveolar bone was detected by immunohistochemistry. The levels of Runx2 mRNA and ALP mRNA in the gingival epithelium were examined by quantitative real-time polymerase chain reaction. Results. LIRA decreased alveolar bone resorption, improved the microstructure of alveolar bone, and reduced periodontal inflammation and damage (P < 0.05). LIRA also reduced blood glucose level and inhibited the secretion of serum IL-6, TNF-alpha, and IL-1 beta (P < 0.05). In addition, after treatment with LIRA, the ratio of RANKL/OPG was reduced, and the expression levels of ALP mRNA and Runx2 mRNA were upregulated (P < 0.05). Conclusions. LIRA not only controls blood glucose level but also reduces inflammation and bone loss and enhances osteogenic differentiation in diabetes-associated periodontitis. Those indicate that LIRA may be used as a potential medicine for the adjunctive therapy of diabetes-periodontitis comorbidity.