Impact of natural curcumin on the progression of experimental periodontitis in diabetic rats.

Objective: To evaluate the role of natural curcumin (CURC) on experimental periodontitis (EP) in animals with diabetes mellitus (DM).
Material and Methods: One hundred rats were assigned to DM + placebo (PLA); DM + CURC; DM + insulin (INS); DM + CURC + INS; and Non-DM. Diabetes was induced by streptozotocin. After 3 days, they were initiated CURC and PLAC solutions and insulin administrations, daily for 30 days. This included a period of 19 days prior to EP induction (ligature at the first mandibular and the second maxillary molar) and then additional 11 days. Specimens from the mandible were processed for morphometric examination of bone level. Gingival tissues from mandibular molars were collected for quantification of IL-1β, IL-4, IL-6, IL-17, IFN-γ, and TNF-α using a Luminex/MAGpix assay. Gingivae from maxillary molars were subjected to RT-PCR for assessment of Runx2, RANKL, OPG, SIRT, Dkk1, and Sost levels.
Results: Lower linear bone loss was detected in ligated molars of DM + CURC + INS vs DM + PLAC and DM + INS groups (P < 0.05). In ligated sites from DM rats treated with CURC + INS, IL-6, IL-1β, INF-γ, and TNF-α levels were the lowest in comparison with PLAC and/or INS and CURC as monotherapies (P < 0.05). CURC, independently of INS, increased Runx2 and SIRT when compared to DM + PLAC (P < 0.05) in ligated sites, whereas only CURC + INS reduced the RANKL/OPG ratio when compared to DM + PLAC (P < 0.05).
Conclusion: Natural CURC, when associated with INS, reduces the DM-induced loss of supporting alveolar bone and promotes favorable modulation on osteo-immune-inflammatory mediators.
(© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)