Antiperiodontitis Effects of Magnolia biondii Extract on Ligature-Induced Periodontitis in Rats

Alveolar Bone Loss in a Ligature-Induced Periodontitis Model in Rat Using Different Ligature Sizes

OBJECTIVES

 Ligature-induced periodontitis model has been widely used as a preclinical stage for investigating new treatment modalities. However, the effect of different ligature sizes on alveolar bone loss has never been studied. Therefore, we examined alveolar bone loss in this rat model using different sizes of silk ligatures, as well as healing after ligature removal.

MATERIALS AND METHODS

 Left maxillary second molars of Sprague-Dawley rats were ligated with 3-0, 4-0, or 5-0 silk ligatures (n = 4-5/group) for 14 days before harvested maxillae and gingival tissues. For subsequent experiment, animals were ligated for 14 days using the ligature size that induced the most alveolar bone loss before ligature removal and sacrificed at 0, 7 and 14 days (n = 5-6/group). All maxillae and gingival tissues were harvested to evaluate alveolar bone level, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) levels.

STATISTICAL ANALYSIS

 Data was analyzed using SPSS Statistics 23.0 software (SPSS Inc., Chicago, Illinois, United States). Data from all experiments were tested for normality using Shapiro-Wilk test. Data between ligatured and nonligatured teeth were compared using Student's t-test or Wilcoxon signed-rank test. Differences among different ligature sizes were analyzed by analysis of variance followed by multiple comparisons with post-hoc test. A p-value less than 0.05 was considered statistically significant.

RESULTS

 The alveolar bone loss of ligated teeth was substantially higher than that of control after 14 days of ligation. While 3-0 and 4-0 resulted in significantly greater bone loss than 5-0 silk, the 3-0 group had the lowest rate of ligature loss. Therefore, alveolar bone healing postligature removal was investigated further using 3-0 silk. The results showed no significant bone level change at 2 weeks after ligature removal. In term of IL-1β and TNF-α levels, there was no statistically significant difference in IL-1β level between groups at any time point, while TNF-α was undetectable.

CONCLUSION

 These data showed that 3-0 silk was the most effective ligature size in promoting alveolar bone loss comparing with 4-0 and 5-0 silk. During the 2-week period following ligature removal, spontaneous bone healing was not observed.

Magnolia kobus Extract Suppresses Porphyromonas gingivalis LPS-Induced Proinflammatory Cytokine and MMP Expression in HGF-1 Cells and Regulates Osteoclastogenesis in RANKL-Stimulated RAW264.7 Cells

Clinical prevention is of utmost importance for the management of periodontal diseases. Periodontal disease starts with an inflammatory response in the gingival tissue, and results in alveolar bone destruction and subsequent tooth loss. This study aimed to confirm the anti-periodontitis effects of MKE. To confirm this, we studied its mechanism of action using qPCR and WB in LPS-treated HGF-1 cells and RANKL-induced osteoclasts. We found that MKE suppressed proinflammatory cytokine protein expression by inhibiting the TLR4/NF-κB pathway in LPS-PG-induced HGF-1 cells and blocking ECM degradation by regulating the expression of TIMPs and MMPs. We also confirmed that TRAP activity and multinucleated cell formation were reduced in RANKL-stimulated osteoclasts after exposure to MKE. These results were confirmed by inhibiting TRAF6/MAPK expression, which led to the suppression of NFATc1, CTSK, TRAP, and MMP expression at the gene and protein levels. Our results confirmed that MKE is a promising candidate for the management of periodontal disease based on its anti-inflammatory effects and inhibition of ECM degradation and osteoclastogenesis.

Anti-Periodontitis Effects of Dendropanax morbiferus H.Lév Leaf Extract on Ligature-Induced Periodontitis in Rats

Periodontitis is caused by pathogens in the oral cavity. It is a chronic infectious disease that causes symptoms including gingival bleeding and tooth loss resulting from the destruction of periodontal tissues coupled with inflammation. Dendropanax morbiferus H.Lév (DM) is a natural product that exhibits various biological activities with few side effects. In this study, the potential of DM leaf hot-water extracts (DMWE) as a treatment for periodontitis was determined and its anti-oxidant and anti-inflammatory effects were evaluated. Compounds in DMWE were identified by high-performance liquid chromatography (HPLC) and nitric oxide (NO) and prostaglandin E₂ (PGE₂) production was measured in RAW 264.7 cells. We measured the gingival index and gingival sulcus depth, and micro-CT was performed in vivo using a ligature-induced periodontitis rat model, which is similar to human periodontitis. The DMWE-treated group exhibited a decrease in cytokine concentration and relieved the gingival index and gingival sulcus depth compared with the periodontitis-induced control group. In addition, micro-CT and histological analysis revealed that DMWE exhibited anti-inflammatory effects and improved alveolar bone loss in periodontitis-induced rats. These findings suggest that DMWE has excellent anti-oxidant and anti-inflammatory effects that protect and prevent periodontal tissue damage and tooth loss caused by the inflammatory response.

Lacticaseibacillus rhamnosus MG4706 Suppresses Periodontitis in Osteoclasts, Inflammation-Inducing Cells, and Ligature-Induced Rats

Periodontitis is a chronic inflammatory disease characterized by tooth loss due to inflammation and the loss of alveolar bone. Periodontitis is closely related to various systemic diseases and is emerging as a global health problem. In this study, we investigated the anti-inflammatory effect of lactic acid bacteria (LAB) in vitro on Porphyromonas gingivalis (P. gingivalis) LPS-activated RAW264.7 and human gingival fibroblasts-1 (HGF-1) cells and the anti-osteoclastogenic effect of LAB on RANKL-induced RAW264.7 cells. All LAB strains (Lacticaseibacillus rhamnosus MG4706, MG4709, and MG4711) inhibited nitric oxide (NO)/inducible nitric oxide synthase (iNOS) in P. gingivalis LPS-activated RAW264.7 cells and pro-inflammatory cytokines (IL-1β and IL-6) and matrix metalloproteinase (MMP-8 and MMP-9) in HGF-1 cells. In addition, LAB treatment inhibited osteoclastogenesis by reducing tartrate-resistant acid phosphatase (TRAP) activity and cathepsin K (CtsK) through the downregulation of nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and c-fos gene expression in RANKL-induced RAW264.7 cells. Administration of MG4706 alleviated alveolar bone loss indices and reduced the gene expression of IL-1β, IL-6, MMP-8, MMP-9, and RANKL/OPG ratio in gingival tissue. In conclusion, L. rhamnosus MG4706 has the potential to alleviate periodontitis.

α-Cyperone Ameliorates Lipopolysaccharide-Induced Inflammation and Apoptosis of Periodontal Ligament Stem Cells via Blocking the Toll-Like Receptor 4/NF-κB Signaling

Periodontitis is a long-lasting inflammatory microbial sickness that could cause damage to the periodontal ligament, gums, cementum and alveolar bone directly. Cyperus rotundus is a common traditional Chinese medicine clinically with many pharmacological activities, α-Cyperone is a bioactive ingredient abundant in Cyperus rotundus, few studies have focused on its anti-fungal and anti-oxidative stress activities in mice, during this research, we firstly investigated the impact of α-Cyperone on PDLSCs inflammatory by LPS stimulation. Our findings illustrated that α-Cyperone exerted no influence on PDLSCs viability at concentrations lower than 60 μM, and the release of inflammatory cytokines decreased with an increase in LPS concentration. Meanwhile, we found that α-Cyperone effectively restrained LPS-induced PDLSC cell apoptosis by CCK-8 cell viability assay and TUNEL-positive staining. Furthermore, the TLR4 expression and NF-κB kinase activation were greatly repressed by α-Cyperone treatment in LPS-induced PDLSCs inflammatory model. Subsequently, enhanced TLR4 expression was observed to reverse the suppressed release of inflammatory cytokines and decreased apoptosis effects mediated by α-Cyperone in LPS-cotreated PDLSCs, indicating that the deactivation of TLR4 and downstream NF-κB were implicated in favoring α-Cyperone-triggered protective effects of LPS in PDLSCs.

Genetic association of the epidermal growth factor gene polymorphisms with peri-implantitis risk in Chinese population

Peri-implant disease is an inflammatory disease and is related to genetic heterogeneity. Considering the genetic association of epidermal growth factor (EGF) gene polymorphisms with the susceptibility of periodontitis, its genetic association with peri-implantitis risk in a Chinese Han population was explored. Three hundred individuals who underwent dental implants were recruited, and divided into healthy implant group and peri-implantitis group. The genotype and allele distribution of EGF gene rs2237051 and rs4444903 polymorphisms were analyzed via direct sequencing and the frequencies were compared between the two groups using chi-square test. No significant difference was detected for the clinical information between healthy implant group and peri-implantitis group, including lifestyle habits platform type and position, peri-implant phenotype, brushing time, dental floss, and mouth washing frequencies. Individuals with peri-implantitis had poor periodontal status. The GG genotype and G allele of rs2237051 showed significant increasing trend in peri-implantitis group compared with the healthy implant group. Compared with the AA genotype carriers, rs2237051 GG genotype carriers showed lower risk to suffer from peri-implantitis (OR = 0.236, 95%CI = 0.089–0.624), and possessed low values of gingival index, plaque index and calculus index, peri-implant pocket depth (PPD) and clinical attachment level (CAL). But there was no significant difference for the rs4444903 genotype distributions between the case and control groups. In summary, EGF rs2237051 polymorphism showed close association with the genetic background of peri-implantitis. Rs2237051 GG genotype and G allele might be protective factors for the onset of peri-implantitis.

Efficacy of bubaline blood derived fibrin glue in silk ligature-induced acute periodontitis in Wistar rats

BACKGROUND AND AIM

Fibrin forms in the coagulation process, enhancing local hemostatic properties and promoting wound healing. The study aimed to evaluate the efficacy of bubaline-derived fibrin glue in silk ligature-induced periodontitis rats.

MATERIALS AND METHODS

Bubaline blood-derived fibrin glue was prepared using cryoprecipitation and cryocentrifugation. Periodontitis was induced in rats by placing 5-0 silk ligatures around the mandibular first molars. The animals were divided into two groups: (1) Non-treatment and (2) bubaline fibrin glue-treated groups. Plaque, gingival inflammation, and mobility index were scored on days 1, 7, and 14 after intervention. Histological examinations were performed. The mRNA expression of inflammatory cytokines and growth factors was evaluated using a real-time polymerase chain reaction. Ligature-induced periodontitis was confirmed by the increase in inflammatory cell infiltration as well as histological bone and attachment loss.

RESULTS

Compared to the non-treatment group, bubaline fibrin glue application reduced mononuclear cell infiltration into periodontal tissues corresponding to the reduction of collagen destruction. On days 7 and 14 after intervention, the inflammatory score and histological attachment loss were significantly lower in the bubaline fibrin glue-treated group than in the non-treatment group. A significant reduction in histological bone loss was observed in the treated group on day 7. Bubaline fibrin glue application led to a significant reduction of Tnfa and Il1b mRNA levels, while an increased expression of Pdgfa, Tgfb1, and Il10 was observed compared with the control.

CONCLUSION

Bubaline fibrin glue could be beneficial in periodontitis treatment aiming to reduce inflammation and delay the progression of periodontal disease.

Structural elucidation and neuroprotective activities of lignans from the flower buds of Magnolia biondii Pamp

Two new lignans, 3,4-(10-methoxy-phenylallyl)-9″-((10'-isopropanol-3',4'-furan)-phenylacetyl)-8″-dioxane-7″-O-β-d-glucopyranoside (1), 3,4-benzolactone-9″-((12'-isopropanol-3',4'-furan)-phenylbutenone)-8″-dioxane-7″-O-β-d-glucopyranoside (2), and nine known lignan derivatives (3-11) were isolated from the flower buds of Magnolia biondii Pamp. for the first time. Their structures were elucidated by 1D and 2D NMR, UV, IR, and MS data, as well as by comparison with those of the references. Compounds (1-11) were evaluated for their neuroprotective activities against 6-OHDA-induced cell death in SH-SY5Y cells. As a result, compounds 1, 2, and 5 exhibited significant neuroprotective activities with IC₅₀ values in the range of 3.08-6.12 μM.

Anti-inflammatory effect of IL-1ra-loaded dextran/PLGA microspheres on Porphyromonas gingivalis lipopolysaccharide-stimulated macrophages in vitro and in vivo in a rat model of periodontitis

Periodontitis is a multifactorial chronic infectious disease leading to a host immune response involving inflammatory cytokines, especially IL-1β, which is the main reason for further developing this disease. IL-1 receptor antagonist (IL-1ra) binds IL-1 receptor, inhibiting IL-1β signaling and reducing the levels of other cytokines closely related to periodontitis, such as IL-6 and TNF-α. Therefore, the use of IL-1ra to inhibit periodontitis development in a system, ensuring its sustained release, might be an effective way to combat this disease. Hence, in this study, a novel IL-1ra-loaded dextran/PLGA microsphere was developed to allow the sustained release of IL-1ra and enhance the anti-inflammatory properties. Therefore, this study's purposes were to develop a novel periodontal treatment for inhibition and treatment of periodontitis and evaluate the sustained-release effect and anti-inflammatory properties of IL-1ra-loaded dextran/PLGA microspheres in vitro by cell experiments and in vivo by animal experiments. The results showed that IL-1ra-loaded dextran/PLGA microspheres were non-toxic both in vitro and in vivo and could be used as a safe and effective treatment. In addition, these microspheres could significantly prolong the half-life of IL-1ra drug, exerting a useful anti-inflammatory effect in macrophages stimulated with P. gingivalis lipopolysaccharide and in rats with periodontitis. In conclusion, IL-1ra-loaded dextran/PLGA microsphere might be a useful tool to combat periodontal disease.