Experimental Periodontitis Model Research Articles

Complement components C3b and C4b as potential reliable site-specific diagnostic biomarkers for periodontitis.

This study aimed to investigate the correlation between the expression levels of C3b and C4b in human gingival tissue (GT) and gingival crevicular fluid (GCF) and disease severity in human periodontitis and to determine whether C3b and C4b are significant site-specific complementary diagnostic markers for periodontitis. A variety of biomarkers that have potential for informing diagnoses of periodontitis have been proposed. The complement components C3b and C4b were found to be positively correlated with disease severity. The therapeutic effect of targeting C3b and C4b on inflammatory bone loss in experimental periodontitis models has been studied. However, studies on the diagnostic potential of the gingival C3b and C4b expression levels for periodontitis are scarce. The expression levels of C3b and C4b in the GT and GCF were investigated via immunohistochemistry and enzyme-linked immunosorbent assay, respectively. The correlation between the expression levels of C3b and C4b and disease severity with probing depth as well as the clinical attachment level were determined. To evaluate the diagnostic accuracy of the C3b and C4b expression levels at the periodontitis sites, the receiver operating characteristic (ROC) curve, cut-off point, area under the ROC curve, sensitivity, and specificity were analyzed. The expression levels of C3b and C4b in human GT and GCF were significantly positively correlated with periodontitis severity. The expression levels of combined C3b + C4b in the GT can significantly differentiate the disease status at the tissue level (p < .0001). Similarly, the expression levels of C3b + C4b in GCF can statistically distinguish periodontitis sites from healthy ones (p < .0001). Locally deposited C3b and C4b were positively correlated with periodontitis severity and recognized as site-specific diagnostic biomarkers for clinicopathological features in periodontitis. The association between the C3b and C4b network and periodontitis may be further understood and provide a basis for the development of novel screening as well as diagnostic and therapeutic strategies for periodontitis.

Effect of periodontitis induced by Fusobacterium nucleatum on the microbiota of the gut and surrounding organs.

Detection of the oral bacterium Fusobacterium nucleatum in colorectal cancer tissues suggests that periodontitis may alter gut microbiota. The purpose of this study was to analyze the influence and infection route of periodontal inflammation caused by F. nucleatum, and microbiota of the gut and surrounding organs (heart, liver, kidney). Wistar female rats were orally inoculated with F. nucleatum to establish an experimental periodontitis model that was confirmed by X-ray imaging and histopathological analysis. The mandibles, gut, liver, heart, and kidneys were collected from the experimental group at 2, 4, and 8weeks, and from the uninfected control group at 0weeks, for DNA extraction for PCR amplification and comprehensive microbiota analysis using the Illumina MiSeq platform. Imaging confirmed the onset of periodontitis at 2weeks post-inoculation, and histopathology showed inflammatory cell infiltration from 2 to 8weeks. PCR and comprehensive microbiota analysis showed the presence of F. nucleatum in the heart and liver at 2weeks, and in the liver at 4 and 8weeks. There were changes of microbiota of the gut, heart, liver, and kidneys at 4weeks: namely, decreased Verrucomicrobia and Bacteroidetes, and increased Firmicutes. F. nucleatum induced the onset of periodontitis and infected the heart and liver in rats. As the periodontic lesion progressed, the microbiota of the gut, liver, heart, and kidneys were altered.

Periodontal ligament-associated protein-1 knockout mice regulate the differentiation of osteoclasts and osteoblasts through TGF-β1/Smad signaling pathway.

It has been known that periodontal ligament-associated protein-1 (PLAP-1/Asporin) not only inhibits cartilage formation in osteoarthritis, but it also influences the healing of skull defect. However, the effect and mechanism of PLAP-1/Asporin on the mutual regulation of osteoclasts and osteoblasts in periodontitis are not clear. In this study, we utilized a PLAP-1/Asporin gene knockout (KO) mouse model to research this unknown issue. We cultured mouse bone marrow mesenchymal stem cells with Porphyromonas gingivalis lipopolysaccharide (P.g. LPS) for osteogenic induction in vitro. The molecular mechanism of PLAP-1/Asporin in the regulation of osteoblasts was detected by immunoprecipitation, immunofluorescence, and inhibitors of signaling pathways. The results showed that the KO of PLAP-1/Asporin promoted osteogenic differentiation through transforming growth factor beta 1 (TGF-β1)/Smad3 in inflammatory environments. We further found the KO of PLAP-1/Asporin inhibited osteoclast differentiation and promoted osteogenic differentiation through the TGF-β1/Smad signaling pathway in an inflammatory coculture system. The experimental periodontitis model was established by silk ligation and the alveolar bone formation in PLAP-1/Asporin KO mice was promoted through TGF-β1/Smad3 signaling pathway. The subcutaneous osteogenesis model in nude mice also confirmed that the KO of PLAP-1/Asporin promoted bone formation by the histochemical staining. In conclusion, PLAP-1/Asporin regulated the differentiation of osteoclasts and osteoblasts through TGF-β1/Smad signaling pathway. The results of this study lay a theoretical foundation for the further study of the pathological mechanism underlying alveolar bone resorption, and the prevention and treatment of periodontitis.

Porphyromonas gingivalis induces an inflammatory response via the cGAS-STING signaling pathway in a periodontitis mouse model.

Periodontitis is an inflammatory disease initiated by periodontopathogenic bacteria in the dental plaque biofilms. Understanding the role of Porphyromonas gingivalis (P. gingivalis), a keystone pathogen associated with chronic periodontitis, in the inflammatory response is crucial. Herein, we investigated whether P. gingivalis infection triggers the expression of the type I IFN gene and various cytokines and leads to activation of the cGAMP synthase-stimulator of IFN genes (cGAS-STING) pathway both in vitro and in a mouse model. Additionally, in an experimental model of periodontitis using P. gingivalis, StingGt mice showed lower levels of inflammatory cytokines and bone resorption than wild-type mice. Furthermore, we report that a STING inhibitor (SN-011) significantly decreased inflammatory cytokine production and osteoclast formation in a periodontitis mouse model with P. gingivalis. In addition, STING agonist (SR-717) -treated periodontitis mice displayed enhanced macrophage infiltration and M1 macrophage polarization in periodontal lesions compared with that in vehicle-treated periodontitis mice. In conclusion, our results demonstrate that the cGAS-STING signaling pathway may be one of the key mechanisms crucial for the P. gingivalis-induced inflammatory response that leads to chronic periodontitis.

Regulation of RIP1-Mediated necroptosis via necrostatin-1 in periodontitis.

To explore the mechanism of receptor-interacting protein 1 (RIP1)-mediated necroptosis during periodontitis progression. RIP3 and mixed lineage kinase domain-like protein (MLKL) have been detected to be upregulated in periodontitis models. Because RIP1 is involved in necroptosis, it might also play a role in the progression of periodontitis. An experimental periodontitis model in BALB/c mice was established by inducing oral bacterial infection. Western blotting and immunofluorescence analyses were used to detect RIP1 expression in the periodontal ligament. Porphyromonas gingivalis was used to stimulate L929 and MC3T3-E1. RIP1 was inhibited using small-interfering RNA. Western blotting, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA) analyses were used to detect the effect of necroptosis inhibition on the expression of damage-associated molecular patterns and inflammatory cytokines. Necrostatin-1 (Nec-1) was intraperitoneally injected to inhibit RIP1 expression in mice. Necroptosis activation and inflammatory cytokine expression in periodontal tissue were verified. Tartrate-resistant acid phosphatase staining was applied to observe osteoclasts in the bone tissues of different groups. RIP1-mediated necroptosis was activated in mice with periodontitis. P. gingivalis induced RIP1-mediated necroptosis in L929 and MC3T3-E1 cells. After RIP1 inhibition, the expression levels of high mobility group protein B1 (HMGB1) and inflammatory cytokines were downregulated. After inhibiting RIP1 with Nec-1 in vivo, necroptosis was also inhibited, the expression levels of HMGB1 and inflammatory cytokines were downregulated, and osteoclast counts in the periodontal tissue decreased. RIP1-mediated necroptosis plays a role in the pathological process of periodontitis in mice. Nec-1 inhibited necroptosis, alleviated inflammation in periodontal tissue, and reduced bone resorption in periodontitis.

DNA damage-inducible transcript 3 deficiency promotes bone resorption in murine periodontitis models.

Periodontitis is a multifactorial inflammatory disease that leads to the destruction of supporting structures of the teeth. DNA damage-inducible transcript 3 (DDIT3) plays crucial roles in cell survival and differentiation. DDIT3 regulates bone mass and osteoclastogenesis in femur. However, the role of DDIT3 in periodontitis has not been elucidated. This research aimed to explore the role and mechanisms of DDIT3 in periodontitis. DDIT3 gene knockout (KO) mice were generated using a CRISPR/Cas9 system. Experimental periodontitis models were established to explore the role of DDIT3 in periodontitis. The expression of DDIT3 in periodontal tissues was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). The alveolar bone phenotypes were observed by micro-CT and stereomicroscopy. The inflammation levels and osteoclast activity were examined by histological staining, immunostaining, and qRT-PCR. Bone marrow-derived macrophages (BMMs) were isolated to confirm the effects of DDIT3 on osteoclast formation and function in vitro. The increased expression of DDIT3 in murine inflamed periodontal tissues was detected. DDIT3 knockout aggravated alveolar bone loss and enhanced expression levels of inflammatory cytokines in murine periodontitis models. Increased osteoclast formation and higher expression levels of osteoclast-specific markers were observed in the inflamed periodontal tissues of KO mice. In vitro, DDIT3 deficiency promoted the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts and the bone resorption activity of mature osteoclasts. Our results demonstrate that DDIT3 deletion aggravated alveolar bone loss in experimental periodontitis through enhanced inflammatory reactions and osteoclastogenesis. The anti-inflammation and the inhibition of bone loss by DDIT3 in murine periodontitis provides a potential novel therapeutic strategy for periodontitis.

Sex effects on gingival transcriptomic patterns during initiation, progression, and resolution of periodontitis.

The prevalence and severity of periodontitis demonstrates altered population distribution with age, sex, and race and ethnicity. While males exhibit greater frequency of disease, particularly with aging, the underlying basis for this observation remains obscure. This study used a nonhuman primate (Macaca mulatta) model of experimental ligature-induced periodontitis in adult animals to evaluate gingival transcriptomic differences stratified based upon sex of the animal. The 18 animals represented humans ages 40-80 years, with gingival tissue samples obtained at baseline, 0.5 months (initiation), 1 and 3 months (progression), and at 5 months that were 60 days after ligature removal for clinical disease resolution. Microarray analysis was used to quantify gene expression profiles in the gingival tissues. The results demonstrated clear gene expression differences in healthy (baseline) tissues between the sexes, with elevations in females associated with immune responses and elevation in males related to tissue structural genes. With disease initiation, fewer genes differed between the sexes, while these differences were significantly increased in progressing disease and resolution, particularly in male animals. Overexpressed biological processes showed tissue structural/functional genes at initiation, with host response pathways altered during disease progression. Resolution samples generally demonstrated biological processes of cellular metabolism that differed from baseline healthy samples. The transcriptomic findings support sex as a biological variable in periodontitis using a nonhuman primate model of experimental periodontitis.

Cannabidiol attenuates periodontal inflammation through inhibiting TLR4/NF-κB pathway.

Periodontitis is a chronic inflammatory disease involving soft and hard tissue destruction in the periodontal region. Cannabidiol (CBD) is a natural compound isolated from cannabis, which has the effect of inhibiting inflammation. However, the role of CBD in periodontitis remains unclear. The aim of this study was to investigate the anti-inflammatory effects and osteoprotective actions of CBD in periodontitis and its molecular mechanisms. After establishing the rat periodontitis model by ligatures, the specimens were processed for morphometric analysis by Micro-CT. The gingival tissues were collected, and the levels of TNF-α, IL-1β, and TLR4 were measured by enzyme-linked immunosorbent assay. LPS was used to induce the inflammatory response of human periodontal ligament cells (hPDLCs) in vitro. QPCR and western blot were carried out to detect the expression of related inflammatory cytokines and signaling pathways. Cannabidiol significantly inhibits bone loss in experimental rat periodontitis models. CBD downregulated the pro-inflammatory mediator TNF-α, related to the decrease of TLR4 protein expression. Overexpression of TNF-α and TLR4 caused by LPS in hPDLCs. CBD inactivated the TLR4/NF-κB signaling pathway by inhibiting TLR-4 expression and p65 NF-κB phosphorylation. CBD can be considered as a therapeutic agent for periodontitis. Our study demonstrated that CBD attenuates ligature-induced periodontitis in rats and LPS-induced inflammation in hPDLCs by inhibiting TLR4/NF-κB pathway activation. It indicates that topical CBD application is effective in treating periodontitis.

Fibroblasts participated in mucosal pathology in the oral disease periodontitis

Abstract The oral cavity is a unique stricture; it combines mucosal and bone tissue microenvironments with their respective immunological responses. In fact, oral mucosal inflammation leads to bone destruction in the prevalent human disease, periodontitis. In periodontitis, immune cells, in particular Th17 and neutrophil mediated responses have been linked to pathogenesis, however it is not yet understood how the stromal tissue microenvironment may participate in disease pathology. To date, studies in humans reveal inflammatory signatures in oral mucosal stromal cells of periodontitis, linked to neutrophil recruitment. To understand fibroblast responses and function in periodontitis, we performed scRNA-seq in mouse oral mucosa during a time course in the experimental periodontitis model. We characterize an early responding fibroblast subpopulation with a distinct inflammatory signature, characterized by induction of the IL33- ST2 cytokine axis. We confirm induction of soluble ST2 in oral mucosal fibroblasts during periodontitis and uncover an immune-regulatory role for ST2 within the oral microenvironment. Our work highlights the nature of oral mucosal immune-responsiveness and provides insights into a common human disease. Supported by NIH intramural funding

Oral mucosa resident CD8 +T cell reactivation exacerbates murine periodontitis

Abstract Periodontitis is the world’s most common chronic inflammatory condition. Progressive forms of periodontitis are initiated by dysbiotic subgingival biofilms yet sustained by unresolved local inflammation. While gingival CD4 +T cells are thought to be major drivers of periodontal inflammation, the role of tissue resident memory (T RM) CD8 +T cells in periodontitis progression and severity remains unknown. We sought to determine whether local reactivation of oral CD8 +T RMof a defined antigen specificity would accelerate ligature-induced periodontitis (LIP), a well-established murine model of experimental periodontitis. Ovalbumin (OVA)-specific OT-I T cells were transferred and expanded though systemic viral infection in naïve hosts. Six-days later, OT-I T cells were ‘pulled’ into the oral mucosa via swabbing of the oral surfaces with OVA peptide in irritants. This approach, collectively referred to as Viral-Prime: Epitope-Pull (VPEP), durably augments oral OT-I T RMin the oral mucosa to manipulate and study. Utilizing ‘VPEP’ memory mice, oral CD8 +T RMwere reactivated with OVA peptide concurrent with LIP. Control mice received oral swabbing with an irrelevant peptide. Alveolar bone loss and interstitial immune infiltrates were characterized using microCT imaging and flow cytometry, respectively. We found that oral T RMreactivation accelerated alveolar bone loss and enriched neutrophils, macrophages and CD8 +T cells within ligature-proximal gingiva. Bulk RNAseq analysis revealed several inflammatory and matrix-remodeling genes induced in maxillary and mandibular gingiva upon oral T RMreactivation. Collectively, we provide evidence that oral CD8 +T RMreactivation can exacerbate periodontitis. This work is supported by NIH/NIDCR grants R90 DE023058 to F.M.S. and T90 DE 022732 &amp; K99DE031014 to J.M.S

Effect of Moringa oleifera on serum YKL-40 level: In vivo rat periodontitis model

Abstract Periodontitis is a chronic inflammatory disease that destroys the bones and soft tissues that support the tooth as a result of inflammatory reactions. YKL-40 is an inflammatory marker associated with inflammation and is also associated with periodontal diseases. Moringa oleifera (MO) is a plant rich in high nutritional values, minerals, vitamins, and other essential phytochemicals. The aim of this study was to investigate the effect of MO administration on serum YKL-40 levels in an experimental periodontitis model. In the study, a total number of 24 female Wistar albino rats, which were 4–5 months old with a body weight of 275 ± 25 g, were used. Animals were divided into three groups. 1st group: Control (n = 8), 2nd group: periodontitis group (PG) (n = 8), 3rd group: Periodontitis group (PG + MO) with an additional 200 mg/kg/4 weeks MO (n = 8). In the PG and PG + MO were formed experimental periodontitis model. Compared to the PG, the decrease in the interleukin-6 (IL-6) and YKL-40 values in the PG + MO (p &lt; 0.05, p &lt; 0.05) was found to be significant in terms of statistical evaluation. As a result, MO decreased YKL-40 levels in the experimental periodontitis model. Although further research is needed, drugs containing MO can be used in the treatment of periodontal diseases.

Preventive Effects of Chlorogenic Acid on Alveolar Bone Loss in Ligature-Induced Periodontitis in Mice

Chlorogenic acid (CGA) is a polyphenol that is present in coffee beans, many vegetables, and fruits. Since CGA has been reported to exert antioxidant and anti-inflammatory effects, it is expected to protect against periodontitis. In the present study, we used a ligature-induced experimental periodontitis model and investigated the beneficial effects of CGA against alveolar bone resorption caused by experimental periodontitis. To examine the inhibitory effects of CGA on bone loss, a ligature was wrapped around the maxillary right second molar, and CGA was intraperitoneally injected once a day for 2 weeks. In another experiment to investigate the restorative effects of CGA on bone loss, a ligature was wrapped around the maxillary right second molar for 2 weeks, it was then removed, and CGA was intraperitoneally injected once a day for 2 weeks. At the end of the experiments, the maxillae were removed, and CT images were taken. Alveolar bone loss was measured as the distance from the cement–enamel junction to the alveolar crest. The statistical analysis was performed using GraphPad Prism6 (Dunn’s multiple comparison test). The results revealed that the ratio of the buccal alveolar bone loss (vs. the bone loss on the nonligated side) induced by ligation was significantly decreased by the administration of CGA (5 mg/kg) for 2 weeks. Moreover, the bone loss ratio on the buccal and palatal sides after 2 weeks of ligation was significantly decreased by the 2-week administration of CGA (5 mg/kg). The present results revealed that CGA exerted preventive effects against alveolar bone loss caused by experimental periodontitis.

Ligature-Induced Periodontitis Drives Colorectal Cancer: An Experimental Model in Mice

Periodontitis is a prevalent inflammatory oral disease associated with an increased risk of colorectal cancer. Experimental animal models are critical tools to investigate the effects and mechanisms of periodontitis on colorectal cancer. Several murine periodontitis models have been used in research, including oral gavage, periodontal pathogen injection, and ligature models. The role of experimental periodontitis caused by silk ligation in colorectal cancer remains unclear. In this study, we used an experimental periodontitis model on a colitis-associated colorectal cancer model and a spontaneous model, respectively. We observed the promotion of colorectal cancer in ligature-induced periodontitis mice compared to those control mice in 2 different models, as assessed by tumor number, tumor size, and tumor load. Since bacterial dysbiosis is an important feature of periodontitis, we next analyzed the oral and gut microbiomes using 16S ribosomal RNA gene sequencing. We found that the experimental periodontitis model reshaped the microbial community in the oral cavity and gut. In addition, we found a higher extent of programmed death 1 (PD-1)–positive CD8+ T-cell infiltration in tumor samples of the periodontitis group than in controls by immunofluorescence staining. Regarding the potential molecular mechanism, we transplanted the fecal microbiota of the periodontitis patient into mice and observed a tumor-promoting effect in the periodontitis group, assessed by tumor volume and tumor weight, together with a low level of INF-γ+ CD8+ T-cell infiltration in subcutaneous tumor mice. Taken together, we show that ligature-induced periodontitis model promotes colorectal cancer by microbiota remodeling and suppression of the immune response.

The tendency of anemia of inflammation in periodontal diseases.

Anemia of inflammation (AI) is associated with inflammatory diseases, and inflammation-induced iron metabolism disorder is the major pathogenic factor. Earlier studies have reported a tendency of AI in periodontitis patients, but the explicit relationship and possible pathological mechanisms remain unclear. Here, the analyses of both periodontitis patients and a mouse model of ligature-induced experimental periodontitis showed that periodontitis was associated with lower levels of hemoglobin and hematocrit with evidence of systemic inflammation (increased white blood cell levels) and evidence of iron restriction (low serum iron along with a high serum hepcidin and ferritin levels), in accordance with the current diagnosis criteria for AI. Moreover, periodontal therapy improved the anemia status and iron metabolism disorders. Furthermore, the increased level of hepcidin and significant correlation between hepcidin and key indicators of iron metabolism emphasized the pivotal role of hepcidin in the pathogenesis of periodontitis-related AI. Administration of the signal transducer and activator of transcription 3 (STAT3) inhibitors Stattic suggested that the IL-6-STAT3-hepcidin signaling pathway participated in this regulatory process. Together, these findings demonstrated that periodontitis should be considered an inflammatory disease that contributes to the development of AI; furthermore, IL-6-STAT3-hepcidin signaling pathway plays a key regulatory role in the pathogenesis of periodontitis-related AI. Our study will provide new insights into the systemic effects of periodontitis, while meaningfully expanding the spectrum of inflammatory diseases that contribute to AI.

Eldecalcitol effectively prevents alveolar bone loss by partially improving Th17/Treg cell balance in diabetes-associated periodontitis.

Background: Diabetes-associated periodontitis (DPD) is an inflammatory and destructive disease of periodontal tissues in the diabetic population. The disease is manifested as more severe periodontal destruction and is more difficult to treat when compared with periodontitis (PD). Eldecalcitol (ELD) is a novel active vitamin D3 analog; however, little clinical evidence is available on its role on improving PD and DPD, and its specific mechanisms remain unclear. In this study, we evaluated the preventative effects of ELD toward PD and DPD and explored its underlying molecular mechanisms. Methods: Experimental PD and DPD mouse models were established by ligation combined with lipopolysaccharide (LPS) from Porphyromonas gingivalis injection in C57BL/6J and C57BLKS/J Iar- + Leprdb/+Leprdb (db/db) mice, respectively. Simultaneously, ELD (0.25μg/kg) was orally administered to mice via an intragastric method. Micro-computed tomography (CT), hematoxylin-eosin (HE) staining, immunohistochemistry (IHC), and tartrate-resistant acid phosphatase (TRAP) staining were used to evaluate alveolar bone alterations in vivo. Flow cytometry, immunofluorescence, and real-time polymerase chain reaction (qRT-PCR) were also used to examine gene expression and probe systemic and local changes in Treg and Th17 cell numbers. Additionally, western blotting and immunofluorescence staining were used to examine changes in STAT3/STAT5 signaling. Results: Micro-CT and HE staining showed that the DPD group had higher alveolar bone loss when compared with the PD group. After applying ELD, alveolar bone loss decreased significantly in both PD and DPD groups, and particularly evident in the DPD group. IHC and TRAP staining also showed that ELD promoted osteoblast activity while inhibiting the number of osteoclasts, and after ELD treatment, the receptor activator of nuclear factor-κB ligand (RANKL) to osteoprotegerin (OPG) ratio decreased. More importantly, this decreasing trend was more obvious in the DPD group. Flow cytometry and qRT-PCR also showed that the systemic Th17/Treg imbalance in PD and DPD groups was partially resolved when animals were supplemented with ELD, while immunofluorescence staining and qRT-PCR data showed the Th17/Treg imbalance was partially resolved in the alveolar bone of both ELD supplemented groups. Western blotting and immunofluorescence staining showed increased p-STAT5 and decreased p-STAT3 levels after ELD application. Conclusion: ELD exerted preventative effects toward PD and DPD by partially rectifying Th17/Treg cell imbalance via STAT3/STAT5 signaling. More importantly, given the severity of DPD, we found ELD was more advantageous in preventing DPD.

Circadian rhythm disruption exacerbates the progression of macrophage dysfunction and alveolar bone loss in periodontitis

Macrophages are highly implicated in the progression of periodontitis, while circadian rhythm disruption (CRD) promotes the inflammatory response of macrophages in many diseases. However, the effects of CRD on periodontitis and the role of macrophages in this process remain unclear. Histone lysinedemethylase6a (Kdm6a), a histone demethylase, has recently been identified as a key regulator of macrophage-induced inflammation. Here, we established an experimental periodontitis model by injecting lipopolysaccharide (LPS) derived from Porphyromonas gingivalis with or without periodontal ligation in mice exposed to an 8-h time shift jet-lag schedule every 3 days. By histomorphometry, tartrate acid phosphatase (TRAP) staining, RT-qPCR, ELISA, immunohistochemistry and immunofluorescence analysis, we found that CRD promoted the inflammatory response, alveolar bone resorption, macrophage infiltration and Kdm6a expression in macrophages. Macrophage-specific Kdm6a knockout mice were further used to elucidate the effects of Kdm6a deficiency on periodontitis. Kdm6a deletion in macrophages rescued periodontal tissue inflammation, osteoclastogenesis, and alveolar bone loss in a mouse model of periodontitis. These findings suggest that CRD may intensify periodontitis by increasing the infiltration and activation of macrophages. Kdm6a promotes the inflammatory response in macrophages, which may participate in aggravated periodontitis via CRD.

Targeting therapeutic agent against C3b/C4b, SB002, on the inflammation-induced bone loss in experimental periodontitis.

To use experimental periodontitis models in rats to investigate the correlation between local expression of the complement components C3b and C4b in periodontal tissues and disease severity, and to assess the therapeutic effects of targeting C3b/C4b on inflammatory bone loss. The gingival expression of C3, C3b, and C4b in animal experimental periodontitis models were analysed immunohistochemically. The therapeutic effects of the C3b/C4b inhibitor (SB002) on ligation-induced experimental periodontitis was examined using biochemical, histological, and immunohistochemical analyses. The gingival expression levels of C3, C3b, and C4b were positively correlated with the severity of periodontitis. Moreover, both single and multiple injections of the C3b/C4b inhibitor had preventive and therapeutic effects on alveolar bone loss in ligation-induced experimental periodontitis with no associated adverse consequences. The association between C3b/C4b and periodontitis may provide a basis for the development of novel therapeutic strategies for periodontitis and other inflammatory diseases.

Metal-organic framework-based nanoplatform enhance fibroblast activity to treat periodontitis.

After periodontal tissue injury, reconstruct soft tissue sealing around the tooth surface is of fundamental importance to treat periodontitis. Among multiple cell types, fibroblast plays a central role in reestablishing functional periodontium. To enhance fibroblast activity, a novel metal-organic framework-based nanoplatform is fabricated using mesoporous Prussian blue (MPB) nanoparticles to load baicalein (BA), named MPB-BA. Drug release test displayed sustained BA release of MPB-BA. Cell proliferation, transwell migration and wound healing tests revealed accelerated fibroblast proliferation and migration for the established MPB-BA nanoplatform. Moreover, vinculin immunofluorescence staining, western blot and quantitative real-time PCR analysis showed up-regulated vinculin protein and integrin α5 and integrin β1 gene expressions for MPB-BA, suggesting improved cell adhesion. In addition, hematoxylin and eosin (H&E) and Masson trichromatic staining suggested superior anti-inflammatory and collagen fiber reconstruction effects for MPB-BA in a rat experimental periodontitis model in vivo. Our study may provide a promising strategy for the treatment of periodontitis.

A modified method for constructing experimental rat periodontitis model.

Background: Periodontitis is a prevalent disease caused teeth lost. The present rat models inducing periodontitis with thread ligature and metal steel ligature have some disadvantages. Methods: We modified the existing rat ligature periodontitis model by fixing the thread ligature on the metal steel ligature passed through the gap between the first and secondmolars of rats with detailed modeling steps and illustrations. We research the pathological process of the periodontitis induced by the modified model, and briefly compared the modified model with the thread ligature model and the metal steel ligature model. Result: Our experimental results showed that there was an aggravation in inflammatory infiltration and alveolar bone resorption in modeling area within 14days of initial induction. After that, the inflammatory infiltration was reduced. And no significant increase in alveolar bone destruction appeared. The modified model was more reliable compared to the thread ligature model, and had greater ability of bacterial aggregation compared to the metal steel ligature model. Conclusion: The modified method covered pathological process of the periodontitis, and showed sufficient efficiency and reliability in inducing rat periodontitis.

Repeated irradiation by light-emitting diodes may impede the spontaneous progression of experimental periodontitis: a preclinical study.

We investigated whether repeated irradiation with light-emitting diodes (LEDs) at a combination of 470 nm and 525 nm could suppress the progression of experimental periodontitis. A experimental periodontitis model was established in the second, third, and fourth premolars of the mandible in beagle dogs for 2 months. The spontaneous progression of periodontitis was monitored under the specified treatment regimen for 3 months. During this period, the animals were subjected to treatments of either plaque control only (control) or plaque control with LED application (test) at 2-week intervals. The clinical parameters included the probing pocket depth (PPD), gingival recession (GR), and the clinical attachment level (CAL). Histomorphometric analysis was performed using measurements of the length of the junctional epithelium, connective tissue (CT) zone, and total soft tissue (ST). There were significant differences in PPD between the control and test groups at baseline and 12 weeks. When the change in PPD was stratified based on time intervals, it was shown that greater differences occurred in the test group, with statistical significance for baseline to 12 weeks, 6 to 12 weeks, and baseline to 6 weeks. There was no significant difference in GR between the control and test groups at any time points. Likewise, no statistically significant differences were found in GR at any time intervals. CAL showed a statistically significant difference between the control and test groups at baseline only, although significant differences in CAL were observed between baseline and 12 weeks and between 6 and 12 weeks. The proportion of CT to ST was smaller for both buccal and lingual areas in the control group than in the test group. Repeated LED irradiation with a combination of 470-nm and 525-nm wavelengths may help suppress the progression of periodontal disease.