Morinda officinalis polysaccharides inhibit the expression and activity of NOD-like receptor thermal protein domain associated protein 3 in inflammatory periodontal ligament cells by upregulating silent information regulator sirtuin 1.

OBJECTIVES: This study aims to investigate the effect of morinda officinalis polysaccharides (MOP) in inflammatory microenvironment on the expression of silent information regulator sirtuin 1 (SIRT1) and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) in periodontal ligament cells. METHODS: Thirty rats were randomly divided into control group (n=6) and model group (n=24). The model group used orthodontic wire ligation to establish periodontitis, and six rats from each group were killed after 3 weeks. The successful modeling was confirmed by Micro-CT. The remaining rats in the model group were randomly divided into natural recovery group, normal saline (NS) group, and MOP group. In the MOP group, MOP [200 mg/(kg·3d), 50 µL for 4 weeks] was injected into the palatal side of the left maxillary first molar of the rats, while the NS group was injected with equal volume of NS. The natural recovery group did not undergo any treatment. The left maxilla tissues of the rats were collected, and pathological changes in perio-dontal ligament cells were observed by hematoxylin-eosin (HE) staining. The expression of SIRT1 and NLRP3 was detected by immunohistochemistry. Cultivate periodontal ligament fibroblasts in vitro and detect the effect of MOP on cell activity using CCK-8. The 4th generation cells were divided into control group, inflammation group (10 µg/mL lipopolysaccharide), and experimental group (5 µmol/L MOP, 5 µmol/L MOP+10 µg/mL lipopolysaccharide). The expression of SIRT1 and NLRP3 was detected by quantitative realtime polymerase chain reaction (qRT-PCR) and Western blot analyses. The acetylation of NLRP3 and the contents of interleukin (IL)-1ß and IL-18 were detected by immunoprecipitation and enzyme-linked immunosorbent assay, respectively. Statistical analysis of data was conducted using Prism 9.0 software. RESULTS: In the vivo experiments, the expression of NLRP3 and SIRT1 in the MOP group decreased significantly compared with that in the natural recovery group and NS group, while the expression of SIRT1 increased (P<0.05) and inflammatory cell infiltration decreased. In the in vitro experiments, the expression of NLRP3 mRNA and protein in the inflammation group increased (P<0.05), while the expression of SIRT1 significantly decreased (P<0.01); MOP upregulated the expression of SIRT1 in inflammatory cells (P<0.05), reduced the expression of NLRP3 and its acetylation level significantly (P<0.05), suppressed the content of IL-1ß and IL-18 in the supernatant (P<0.01). CONCLUSIONS: The SIRT1 expression decreased, and that of NLRP3 expression increased in inflammatory periodontal ligament cells. MOP intervention promoted SIRT1 expression, resulting in the inhibition of NLRP3. Meanwhile, the acetylation level of NLRP3 reduced through deacetylation, leading to the decreased activity of NLRP3. Thus, MOP acted as inflammatory suppressor.

[Effects of chitosan oligosaccharide on alveolar bone resorption, Th17/Treg balance and OPG/RANKL/RANK pathway in periodontitis rats].

PURPOSE: To investigate the effect of chitosan oligosaccharide on alveolar bone resorption, Th17/Treg balance and OPG/RANKL/RANK pathway in rats with periodontitis. METHODS: Rat model of periodontitis was established, and the periodontitis rats were randomly divided into model group, low-dose chitosan oligosaccharide group, middle-dose chitosan oligosaccharide group, high-dose chitosan oligosaccharide group and metronidazole group, with 12 rats in each group, another 12 rats were set as control group. After treatment, gingival index and alveolar bone absorption were evaluated. H-E staining was used to observe the pathological changes of periodontal tissues. The ratio of Th17/Treg cells in peripheral blood was detected by flow cytometry, the levels of serum IL-17, TGF-ß, RANKL and OPG were detected by ELISA, and the expressions of OPG and RANKL mRNA in periodontal tissues of rats in each group were detected by real-time fluorescent quantitative PCR(qRT-PCR). SPSS 24.0 software package was used to analyze the data. RESULTS: Compared with the control group, the periodontal tissue of the model group showed periodontal membrane fiber bundle rupture, disordered arrangement, capillary expansion, proliferation, inflammatory cell infiltration and other pathological damage. Gingival index, alveolar bone resorption value, Th17/Treg ratio, serum RANKL and IL-17 levels, and periodontal RANKL mRNA level were significantly increased(P<0.05), while the levels of serum OPG, TGF-ß and OPG mRNA in periodontal tissues were significantly decreased (P<0.05). Compared with the model group, the pathological damage of periodontal tissue in the low-middle-and high-dose chitosan oligosaccharide groups and metronidazole group was reduced; gingival index, alveolar bone resorption value, Th17/Treg ratio, serum RANKL and IL-17 levels, and periodontal RANKL mRNA level were significantly decreased(P<0.05), while the levels of serum OPG, TGF-ß and OPG mRNA in periodontal tissues were significantly increased(P<0.05); there was a dose-dependent relationship between the chitosan oligosaccharide groups, and there was no significant difference between the high-dose chitosan oligosaccharide group and metronidazole group(P>0.05). CONCLUSIONS: Chitosan oligosaccharide can promote Th17/Treg balance to return to normal, up-regulate OPG expression, down-regulate RANKL expression, inhibit alveolar bone resorption in periodontitis rats and improve their clinical symptoms.

Effects of Different Levels of Caregiver Training on Oral Hygiene After Stroke.

OBJECTIVES: To investigate the effects of caregiver training on poststroke oral hygiene and to identify appropriate structures for training programs. DESIGN: Single-blind prospective cohort study. SETTING: Haikou, China. PARTICIPANTS: Individuals in home care who have had a stroke (N = 150) and their caregivers (N = 150). Eligibility criteria were stable condition, no recent use of antibiotics or periodontal therapy, presence of Ramfjord teeth or neighboring substitutes, and satisfactory Montreal Cognitive Assessment and Burke Water Swallow Test scores. INTERVENTION: Limited (LOHI) or comprehensive (COHI) oral hygiene instructions. MEASUREMENTS: Plaque Index (PI) and Gingival Index (GI) scores (ranging from 0 to 3 for both). RESULTS: Twenty care recipients and their caregivers dropped out during the study. In the care recipient groups, PI and GI scores in the COHI group were lower than in the control and LOHI groups at the end of the second and third month (P < .001). Decline in PI and GI scores in the COHI group started from the first month (P < .001). In the caregiver groups, GI and PI scores in the COHI group were lower than in the control and LOHI groups after baseline (P < .001). Decline in PI and GI scores in the COHI group started from the second month (P < .001), although no group achieved clinically satisfactory levels. Multiple regression analysis revealed that care recipients' PI was correlated with caregivers' PI, number of sessions, and group allocation, as was care recipients' GI with caregivers' GI, number of sessions, and group allocation. CONCLUSION: Additional assessment of program components is necessary to produce clinically significant outcomes. Caregiver PI and GI scores may serve as objective measures of their oral hygiene skills, which can be improved with comprehensive instructions.

Correlation of chronic periodontitis in tropical area and IFN-γ, IL-10, IL-17 levels.

OBJECTIVE: To evaluate the correlation of chronic periodontitis in tropical area and IFN-γ, IL-10 and IL-17 levels. METHODS: One hundred and forty-eight patients and one hundred and thirty-two healthy control subjects were included in the study. Clinical parameters (PI, GI and PD) and GCF levels of IFN-γ, IL-10 and IL-17 were measured at baseline, week 8, week 16 and week 24 after mechanical removal of dental plaque. IFN-γ and IL-10 were determined with ELISA methods and IL-17 was determined with the cytometric bead array. RESULTS: Removal of dental plaque resulted in improvement in all clinical parameters. Meanwhile, GCF IL-17 declined to control levels, while GCF IFN-γ and IL-10 levels remained unchanged. CONCLUSIONS: The decline of GCF IL-17 levels in patients with resolution of periodontitis suggests that IL-17 is involved in the periodontal inflammatory process.