Effects of annatto tocotrienol on rats with periodontitis and hypertension

Abstract

Periodontitis has been linked to endothelial dysfunction and blood pressure elevation in hypertensive patients. The management of these diseases is costly. Recent progress in natural products has shown beneficial activity of annatto tocotrienol from Bixa orellana in preventing and treating systemic diseases. This research aimed to investigate the protective effect of annatto tocotrienol on periodontitis and hypertension using adult male Wistar rats which were divided into seven groups: 1) sham; 2) NG- nitro-Larginine methyl ester (L-NAME); 3) L-NAME + annatto tocotrienol (60 mg/kg/day, oral); 4) periodontitis; 5) periodontitis + annatto tocotrienol; 6) L-NAME + periodontitis; 7) L-NAME + periodontitis + annatto tocotrienol. L-NAME (40 mg/kg) was administered intraperitoneally for 14 days to induce hypertension. A 0.2 mm orthodontic wire was ligated on right maxillary second molar to induce periodontitis. Then, the rats were treated with annatto tocotrienol (60 mg/kg) for 28 days. The blood pressure was measured using the tail-cuff method at baseline, post L-NAME injection (week 3), post ligation (week 7) and post annatto tocotrienol treatment (week 11). Plasma was collected before the study and after treatment for analyses of nitric oxide and pro-inflammatory cytokines using Griess assay and ELISA. After 28 days, the maxillae were extracted to determine alveolar bone loss and the percentage of bone remaining using micro-computed tomography. The data were analysed using one-way analysis of variances (ANOVA), Tukey’s post hoc and Dunnet T3 post hoc test for multiple comparisons between groups. Treatment with annatto tocotrienol reduced periodontitis-induced alveolar bone loss in hypertensive rats based on the percentage of bone remaining and alveolar bone loss analysis (p<0.01). Annatto tocotrienol was also found to reduce blood pressure in rats with hypertension and periodontitis (p<0.05). However, there was no reduction in IL-6, IL-1β and TNF-α levels after annatto tocotrienol treatment. In conclusion, annatto tocotrienol reduced blood pressure, improved the percentage of bone remaining and alveolar bone loss but did not affect the levels of nitric oxide and pro-inflammatory cytokines in rats with periodontitis and hypertension. Hence, further protective effect of annatto tocotrienol can be explored to recommend its potential clinical application for the management of periodontitis and hypertension