Effect of Curcumin on Bone Tissue in the Diabetic Rat: Repair of Peri-implant and Critical-sized Defects

This study determined the effect of curcumin on bone healing in animals with diabetes mellitus (DM). One hundred rats were divided into five groups: DM+PLAC, DM+CURC, DM+INS, DM+CURC+INS, and non-DM (CURC, curcumin; PLAC, placebo; INS, insulin). Critical calvarial defects were created and titanium implants were inserted into the tibiae. Calvarial defects were analyzed histometrically, and BMP-2, OPN, OPG, RANKL, Runx2, Osx, β-catenin, Lrp-5, and Dkk1 mRNA levels were quantified by PCR. The implants were removed for a torque evaluation, the peri-implant tissue was collected for mRNA quantification of the same bone-related markers, and the tibiae were submitted to micro-computed tomography. The DM+CURC+INS and non-DM groups exhibited greater closure of the calvaria when compared to the DM+PLAC group (P<0.05). Increased retention of implants was observed in the DM+CURC, DM+CURC+INS, and non-DM groups when compared to the DM+PLAC group (P<0.05). CURC improved bone volume and increased bone-implant contact when compared to DM+PLAC (P<0.05). In calvarial samples, CURC favourably modulated RANKL/OPG and Dkk1 and improved β-catenin levels when compared to DM+PLAC (P<0.05). In peri-implant samples, Dkk1 and RANKL/OPG were down-regulated and BMP-2 up-regulated by CURC when compared to DM+PLAC (P<0.05). CURC reverses the harmful effects of DM in bone healing, contributing to the modulation of bone-related markers.