Selective cyclooxygenase-2 inhibition prevents alveolar bone loss in experimental periodontitis in rats

Induced Periodontitis in Rats With Three Ligature Types: An Exploratory Study

BACKGROUND

The placement of ligatures in the cervical area of rat molars is considered as a predictable model to induce periodontitis.

OBJECTIVES

The present explorative study aimed to compare the efficacy of metal wires (MWs), without or with sandblasting, versus silk ligatures (SLs) in inducing periodontal bone loss in rats.

MATERIALS AND METHODS

Twenty-four Wistar rats were randomly divided into three groups of eight rats that received three different types of ligatures (MW, sandblasted wire [SMW], and SL) around their first right mandibular molar, while the contralateral tooth was left without the ligature and served as a control. Bone loss was assessed by measuring the distance from the cementoenamel junction (CEJ) to the bone crest at the distal aspect of the first molar on central mesiodistal sections generated from micro-CT scans taken 24 and 35 days after ligature placement.

RESULTS

In the SL group, only in two rats the ligatures were retained until the end of the 24-day period; in all other animals, the ligatures were lost at some time point. In the SMW, the ligatures were retained only for the 24-day period. In the MW group, no ligatures were lost. Irrespective of the group or experimental period, the difference in the crestal bone level between ligated and control teeth was in most cases z < 0.20 mm, that is, in 19 out of 25 pairs of teeth. In a few cases, the bone crest was more apically located at the control teeth compared to the ligated ones (four cases each, during both 24- and 35-day experimental periods).

CONCLUSIONS

Bone loss was minimal during the experimental period, with no significant differences between the test and control teeth, or among the three types of ligatures. MWs, not even roughened, do not seem to be a better alternative to SLs for inducing bone loss in the experimental periodontitis model in the rat. This assumption, however, has to be confirmed in a larger, well-powered study.

A reliable deep-learning-based method for alveolar bone quantification using a murine model of periodontitis and micro-computed tomography imaging

OBJECTIVES

This study focuses on artificial intelligence (AI)-assisted analysis of alveolar bone for periodontitis in a mouse model with the aim to create an automatic deep-learning segmentation model that enables researchers to easily examine alveolar bone from micro-computed tomography (µCT) data without needing prior machine learning knowledge.

METHODS

Ligature-induced experimental periodontitis was produced by placing a small-diameter silk sling ligature around the left maxillary second molar. At 4, 7, 9, or 14 days, the maxillary bone was harvested and processed with a µCT scanner (µCT-45, Scanco). Using Dragonfly (v2021.3), we developed a 3D deep learning model based on the U-Net AI deep learning engine for segmenting materials in complex images to measure alveolar bone volume (BV) and bone mineral density (BMD) while excluding the teeth from the measurements.

RESULTS

This model generates 3D segmentation output for a selected region of interest with over 98 % accuracy on different formats of µCT data. BV on the ligature side gradually decreased from 0.87 mm3 to 0.50 mm3 on day 9 and then increased to 0.63 mm3 on day 14. The ligature side lost 4.6 % of BMD on day 4, 9.6 % on day 7, 17.7 % on day 9, and 21.1 % on day 14.

CONCLUSIONS

This study developed an AI model that can be downloaded and easily applied, allowing researchers to assess metrics including BV, BMD, and trabecular bone thickness, while excluding teeth from the measurements of mouse alveolar bone.

CLINICAL SIGNIFICANCE

This work offers an innovative, user-friendly automatic segmentation model that is fast, accurate, and reliable, demonstrating new potential uses of artificial intelligence (AI) in dentistry with great potential in diagnosing, treating, and prognosis of oral diseases.

Bioactive injectable mucoadhesive thermosensitive natural polymeric hydrogels for oral bone and periodontal regeneration

Periodontitis is an inflammation-related condition, caused by an infectious microbiome and host defense that causes damage to periodontium. The natural processes of the mouth, like saliva production and eating, significantly diminish therapeutic medication residency in the region of periodontal disease. Furthermore, the complexity and diversity of pathological mechanisms make successful periodontitis treatment challenging. As a result, developing enhanced local drug delivery technologies and logical therapy procedures provides the foundation for effective periodontitis treatment. Being biocompatible, biodegradable, and easily administered to the periodontal tissues, hydrogels have sparked substantial an intense curiosity in the discipline of periodontal therapy. The primary objective of hydrogel research has changed in recent years to intelligent thermosensitive hydrogels, that involve local adjustable sol-gel transformations and regulate medication release in reaction to temperature, we present a thorough introduction to the creation and efficient construction of new intelligent thermosensitive hydrogels for periodontal regeneration. We also address cutting-edge smart hydrogel treatment options based on periodontitis pathophysiology. Furthermore, the problems and prospective study objectives are reviewed, with a focus on establishing effective hydrogel delivery methods and prospective clinical applications.

Effects of Coriander on the Repair Process of Experimentally-induced Periodontitis in Rats

The aim of this study was to evaluate the effects of Coriandrum sativum L. (CSL) seed extract on gingival levels of antioxidant enzymes, pro-inflammatory cytokines and on alveolar bone and attachment levels after experimental periodontitis induction in rats and compare it with low-dose doxycycline (LDD). Forty adult male Wistar Albino rats were divided randomly into 5 groups as follows: 1 = periodontally healthy (control); 2 = periodontitis; 3 = periodontitis + CSL (32 mg/kg); 4 = periodontitis + CSL (200 mg/kg); and 5 = periodontitis + LDD (6 mg/kg). Gingival superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) levels were evaluated by enzyme-linked immunosorbent assay. The presence of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1βeta (IL-1β) immunoreactivity was detected immunohistochemically. Alveolar bone area in the furcation space (ABA), alveolar bone loss (ABL), and attachment loss (AL) were evaluated histomorphometrically. The SOD level was lower in group 5 than in groups 2, 3, and 4. The IL-1β level was highest in group 4. The TNF-α level was statistically higher in groups 2 and 4 than in groups 1, 3, and 5. The IL-6 level was highest in group 4. Its level was higher in groups 2 and 3 than in group 5. ABA was less in groups 2, 3, and 4 compared to groups 1 and 5. ABL was less in group 5 than in groups 2, 3, and 4. AL was greater in group 4 than in group 5. The use of 200 mg/kg CSL showed a pro-inflammatory effect and IL-1β and TNF-α levels decreased after 32 mg/kg CSL application in the treatment of periodontitis.

Chlorhexidine gel topical application ameliorates inflammatory bone loss in experimental periodontitis

OBJECTIVES

This study aimed to evaluate the impact of chlorhexidine (CHX) gel on inflammation-induced periodontal tissue destruction, osteoclastogenesis, subgingival microbiota, and on the modulation of the RANKL/OPG as well as inflammatory mediators during bone remodeling in vivo.

MATERIALS AND METHODS

Ligation- and LPS injection-induced experimental periodontitis were created to investigate the effect of topical application of CHX gel in vivo. Alveolar bone loss, osteoclast number and gingival inflammation was evaluated by micro-CT, histological, immunohistochemistry and biochemical analysis. The composition of the subgingival microbiota was characterized by 16S rRNA gene sequencing.

RESULTS

Data shows significant decreases in the alveolar bone destruction in rats from ligation-plus-CHX gel group compared to ligation group. In addition, significant decreases in the number of osteoclasts on bone surface and the protein level of receptor activator of nuclear factor κB ligand (RANKL) in gingival tissue were observed in rats from ligation-plus-CHX gel group. Moreover, data shows significantly decreased inflammatory cell infiltration and decreased expression of cyclooxygenase (COX-2) and inducible NO synthase (iNOS) in gingival tissue from ligation-plus-CHX gel group versus ligation group. Assessment of the subgingival microbiota revealed changes in rats with CHX gel application treatment.

CONCLUSION

HX gel presents protective effect on gingival tissue inflammation, osteoclastogenesis, RANKL/OPG expression, inflammatory mediators, and alveolar bone loss in vivo, which may have a translational impact on the adjunctive use in the management of inflammation-induced alveolar bone loss.

Ixeris dentata and Lactobacillus gasseri media protect against periodontitis through Nrf2-HO-1 signalling pathway

Periodontitis is an infectious inflammation in the gums characterized by loss of periodontal ligaments and alveolar bone. Its persistent inflammation could result in tooth loss and other health issues. Ixeris dentata (IXD) and Lactobacillus gasseri media (LGM) demonstrated strong antioxidant activity, which may prevent oxidative and inflammatory periodontitis. Here, IXD and LGM extracts were investigated for antioxidative activity against oral discomfort and evaluated for their synergistic effect against oxidative and inflammatory periodontitis in a mouse model. IXD/LGM suppressed pro-inflammatory cytokines like interleukin (IL)-1β, IL-6, and TNF-α. Additionally, it reduced pro-inflammatory mediators, nitric oxide, iNOS (inducible nitric oxide synthase), and COX-2 (cyclooxygenase-2) and enhanced AKT, Nrf2, and HO-1 activation. Similarly, IXD/LGM treatment elevated osteogenic proteins and mRNAs; alkaline phosphatase, collagen type 1 (COL1), osteopontin (OPN), and runt-related transcription factor 2 (RUNX2). Hematoxylin and Eosin (H&E) staining and micro-CT analysis confirm the positive impact of IXD/LGM on the periodontal structure and its associated inflammation. These findings demonstrate that IXD/LGM inhibits oxidative stress, periodontal inflammation, and its resultant alveolar bone loss in which Akt (also known as protein kinase B)-nuclear factor-erythroid 2-related factor 2 (Nrf2)-hemoxygenase-1 (HO-1) signaling is involved. Thus, IXD/LGM is a potential candidate against oxidative/inflammatory stress-associated periodontitis.

Temporal changes of periodontal tissue pathology in a periodontitis animal model

PURPOSE

This study aimed to characterize the early stages of periodontal disease and determine the optimal period for its evaluation in a mouse model. The association between the duration of ligation and its effect on the dentogingival area in mice was evaluated using micro-computed tomography (CT) and histological analysis.

METHODS

Ninety mice were allocated to an untreated control group or a ligation group in which periodontitis was induced by a 6-0 silk ligation around the left second maxillary molar. Mice were sacrificed at 1, 2, 3, 4, 5, 8, 11, and 14 days after ligature placement. Alveolar bone destruction was evaluated using micro-CT. Histological analysis was performed to assess the immune-inflammatory processes in the periodontal tissue.

RESULTS

No significant difference in alveolar bone loss was found compared to the control group until day 3 after ligature placement, and a gradual increase in alveolar bone loss was observed from 4 to 8 days following ligature placement. No significant between-group differences were observed after 8 days. The histological analysis demonstrated that the inflammatory response was evident from day 4.

CONCLUSIONS

Our findings in a mouse model provide experimental evidence that ligature-induced periodontitis models offer a consistent progression of disease with marginal attachment down-growth, inflammatory infiltration, and alveolar bone loss.

Analysis of Th-cell subsets in local and systemic environments from experimental periodontitis rats

OBJECTIVES

The objective of this study was to explore the effect of periodontitis on Th-cell subsets in local and systemic environments.

METHODS

A total of 32 male Sprague-Dawley rats were randomly divided into periodontitis and control groups. Silk ligatures were applied to the mandibular first (M1) molars in the periodontitis group. Inflammation and alveolar bone loss around the M1 molars were analyzed by histological staining and microcomputed tomography. The mRNA expression of interferon-γ (IFN-γ), interleukin 4 (IL-4), IL-17, and IL-10 in the gingiva was measured by qRT-PCR. The proportions of Th1, Th2, Th17, and Treg cells in the submandibular lymph nodes, peripheral blood, and jaw bone marrow were tested using flow cytometry.

RESULTS

More inflammatory cells and alveolar bone resorption were found in the periodontitis group, with upregulated mRNA expression of IFN-γ, IL-17, and IL-10. The proportion of Th1 and Th17 cells was significantly elevated in submandibular lymph nodes, and the proportion of Th1, Th2, and Th17 cells was significantly elevated in peripheral blood, while the proportion of Th1, Th17, and Treg cells was significantly elevated in jaw bone marrow in the periodontitis group.

CONCLUSION

This study suggests that periodontitis affects the differentiation of Th-cell subsets in both local and systemic environments, resulting in an increased proportion of proinflammatory cells.

Modulation of oral cancer and periodontitis using chemotherapeutic agents - A narrative review

Periodontitis, an inflammatory condition, is linked to a higher risk of developing oral cancer. Periodontitis may be a precipitating factor for tumorigenesis and the aggressiveness of specific cancer variants. Although genetics is considered the primary etiologic factor for the development of most cancers, many factors have come to be recognized in the initiation and progression of oral cancer. Consecutively, it is suggestive that periodontitis and oral cancer are distinct disease entities but share common pathogenic mechanisms. Oxidative stress and epigenetic mechanisms are among the most researched mechanisms responsible for initiating apoptotic mechanisms implicated in periodontitis and oral cancer. Current research aims to formulate therapeutic agents to intercede in these mechanisms via host modulation therapy and epigenetic therapy. These advances can revolutionize the treatment of periodontitis and oral cancer. This review aims to shed light on the common pathogenic mechanisms of these diseases and the various host modulation agents that could be beneficial in their treatment.

Host Response Modulation Therapy in the Diabetes Mellitus—Periodontitis Conjuncture: A Narrative Review

The inflammatory response of the host in periodontitis is the phenomenon that underlies the onset and evolution of periodontal destructive phenomena. A number of systemic factors, such as diabetes mellitus (DM), can negatively affect the patient with periodontitis, just as the periodontal disease can aggravate the status of the DM patient. Host response modulation therapy involves the use of anti-inflammatory and anti-oxidant products aimed at resolving inflammation, stopping destructive processes, and promoting periodontal healing, all important aspects in patients with high tissue loss rates, such as diabetic patients. This paper reviews the data available in the literature on the relationship between DM and periodontitis, the main substances modulating the inflammatory response (nonsteroidal anti-inflammatory drugs, sub-antimicrobial doses of doxycycline, or omega-3 fatty acids and their products, specialized pro-resolving mediators), as well as their application in diabetic patients.

Comparative Testing of Two Ligature-Induced Periodontitis Models in Rats: A Clinical, Histological and Biochemical Study

Simple Summary

This study is the first study comparing the same parameters of inflammation in two periodontal disease experimental models proposed by the literature and used in the research. The importance of the method used to induce periodontitis in animals resides in the efficacy of proposed technologies and treatments used in preclinical trials. The inflammatory markers Interleukin-1 alpha(IL-1α), Tumor Necrosis Factor-alpha (TNF-α), and high sensitive C reactive protein (hsCRP), the hematological analyses, and the histological probes showed a similar and reproducible periodontal inflammation for the molar induced periodontitis model. Ligation-induced periodontitis in rats has limitations and will never reproduce all aspects of periodontal disease in humans. The findings of this study with the complex association between clinical, biochemical, and histological aspects of the two experimental models of periodontal pathology induction in rats suggest that a similar periodontal pathology to the one we find in humans is best replicated in rats with the molar induced periodontitis model.

Abstract

Experimental animal models for studying the mechanisms of periodontitis and its links are a better alternative to in vitro studies. The aim of this study is to compare two ligature induced periodontitis models and validate the best one for further use in research. An experimental study was performed on male Wistar rats that were divided into three groups: Test 1 (n = 10), incisor ligated, Test 2 (n = 10), molar ligated, and Control (n = 10). The animals were clinically evaluated at the beginning and at the end of the experiment by recording body weight, gingival bleeding index, tooth mobility score, changes in color, and consistency of gingival tissue. Two blood samples were obtained for each animal at baseline and at the end of the experiment. The hematological parameters Interleukin-1 alpha (IL-1 α), high sensitive C Reactive Protein (hsCRP), and Tumor Necrosis Factor-alpha (TNF-α) were measured. Seven days after the induction of periodontitis, the animals were sacrificed, and samples were prepared for histological evaluation. The results of this research demonstrated that the association between clinical, histological, and biochemical parameters initiate a periodontal pathology in the molar induced model in rats while the incisor experimental model initiates only a moderate and incomplete periodontal inflammation, mainly due to mechanical irritation.

Future Drug Targets in Periodontal Personalised Medicine-A Narrative Review

Periodontal disease is an infection-driven inflammatory disease characterized by the destruction of tooth-supporting tissues. The establishment of chronic inflammation will result in progressive destruction of bone and soft tissue changes. Severe periodontitis can lead to tooth loss. The disease has complex pathogenesis with an interplay between genetic, environmental, and host factors and pathogens. Effective management consists of plaque control and non-surgical interventions, along with adjuvant strategies to control inflammation and disrupt the pathogenic subgingival biofilms. Recent studies have examined novel approaches for managing periodontal diseases such as modulating microbial signaling mechanisms, tissue engineering, and molecular targeting of host inflammatory substances. Mounting evidence suggests the need to integrate omics-based approaches with traditional therapy to address the disease. This article discusses the various evolving and future drug targets, including proteomics, gene therapeutics, vaccines, and nanotechnology in personalized periodontal medicine for the effective management of periodontal diseases.

Molecular docking study and antireabsorptive activity of a semi-synthetic coumarin derivative from Platymiscium floribundum in the ligature-induced periodontitis in rats: the involvement of heme oxygenase-1

OBJETIVE

This study aimed to evaluate the anti-resorptive activity of a semi-synthetic coumarin derivative from Platymiscium floribundum, named 6,7-dimethoxy-3-nitrocoumarin.

MATERIAL AND METHODS

Molecular docking studies were performed to test the binding performance of the derivative against targets associated with alveolar bone loss (TNF-α, IL-1β, and catalase) and a target considered an antioxidant defense (HO-1) during periodontitis. Periodontitis was induced by placing a nylon ligature around the second molars. The rats received for 11 days 6,7-dimethoxy-3-nitrocoumarin (0.01, 0.1, or 1 mg/kg) or vehicle. We investigated by RT-qPCR analysis (TNF-α, IL-1β, and HO-1 mRNA expression levels) and by colorimetric assay (catalase activity) the mechanism of action mediated by 6,7-dimethoxy-3-nitrocoumarin. The in vivo toxicity of 6,7-dimethoxy-3-nitrocoumarin was evaluated.

RESULTS

6,7-Dimethoxy-3-nitrocoumarin (0.1 or 1 mg/kg) reduced alveolar bone loss (1.05 ± 0.24), when compared to vehicle-treated group (3.05 ± 0.30). The interactions of 6,7-dimethoxy-3-nitrocoumarin and the four targets (TNF-α, IL-1β, catalase, and HO-1) showed firm bonds above 6.0 kcal/mol. 6,7-dimethoxy-3-nitrocoumarin (1 mg/kg) lowered mRNA expression levels of TNF-α (2.33 ± 0.56) and IL-1β (19.87 ± 2.9), while it increased both the mRNA expression levels of HO-1 (43.40 ± 1.05) and the catalase activity (46.42 ± 4.59), when compared to vehicle-treated group (46.29 ± 8.43; 37.83 ± 4.38; 1.58 ± 0.11; 8.93 ± 1.86, respectively). The animals did not show any signs of toxicity.

CONCLUSION

6,7-Dimethoxy-3-nitrocoumarin decreased inflammatory bone loss in the ligature-induced periodontitis in rats, and the activation of the HO-1 pathway may contribute, at least partially, to its protective effects by reducing TNF-α and IL-1β mRNA levels and increasing catalase activity.

CLINICAL RELEVANCE

6,7-Dimethoxy-3-nitrocumarin could be used as an adjunct to subgingival instrumentation during active and supportive periodontal treatment.

Protective effects of non-thermal plasma on triethylene glycol dimethacrylate-induced damage in odontoblast-like MDPC-23 cells

AIM

To evaluate whether the use of non-thermal plasma (NTP) could reduce triethylene glycol dimethacrylate (TEGDMA)-mediated damage in MDPC-23 cells.

METHODOLOGY

The effects of NTP and TEGDMA on MDPC-23 cell proliferation were tested using WST-1 assays after pretreatment with NTP for 1 min and exposure to TEGDMA. Live/Dead assays were used to visualize cell death. To monitor the effects of NTP and TEGDMA on the cell cycle and apoptotic cell death, flow cytometry was performed. Western blotting was used to assess changes in protein levels mediated by NTP and TEGDMA treatment, and enzyme-linked immunosorbent assays were performed to evaluate the effects of NTP and TEGDMA on prostaglandin E₂ (PGE₂ ) expression. One-way analysis of variance and Duncan's post hoc tests were used for statistical analysis.

RESULTS

NTP treatment effectively protected cells from TEGDMA-mediated cell damage and blocked TEGDMA-mediated cell growth inhibition (p < .05). NTP appeared to protect cells from death (p < .05) and blocked TEGDMA-mediated apoptotic cell death. Additionally, NTP reduced TEGDMA-mediated apoptotic activation of poly (ADP) ribose polymerase-1 and caspase-3 (p < .05). Furthermore, NTP effectively reduced TEGDMA-mediated expression of cyclooxygenase-2 and PGE₂ proteins by inhibiting nuclear factor-κB protein expression (p < .05).

CONCLUSIONS

NTP alleviated TEGDMA-mediated adverse effects by reducing cytotoxicity and inflammatory reactions in cells exposed to TEGDMA.

Celecoxib treatment dampens LPS-induced periapical bone resorption in a mouse model

AIM

To evaluate the efficacy of selective and nonselective inhibitors of cyclooxygenase-2 enzymes in the treatment of experimental apical periodontitis induced by bacterial lipopolysaccharide (LPS) in vivo in a mouse model.

METHODOLOGY

Thirty-six C57BL/6 mice were used. After access cavity preparation, a solution containing E. coli LPS (1.0 µg µL^-1 ) was inoculated into the root canals of the mandibular and maxillary right first molars (n = 72) After 30 days, apical periodontitis was established and the animals were systemically treated with celecoxib, a selective COX-2 inhibitor (15 mg kg^-1 ), or indomethacin, a nonselective COX-2 inhibitor (5 mg kg^-1 ), for 7 and 14 days. Blocks containing teeth and bone were removed for histopathological and histometric analyses (haematoxylin and eosin), evaluation of osteoclasts numbers (tartrate-resistant acid phosphatase enzyme - TRAP) and immunohistochemistry for RANK, RANKL and OPG. Gene expression was performed using reverse transcription and real-time polymerase chain reaction (qRT-PCR) for RANK, RANKL, OPG, TRAP, MMP-9, cathepsin K and calcitonin receptor. Histopathological, histometric, TRAP, immunohistochemistry and qRT-PCR data were evaluated using Kruskal-Wallis followed by Dunn's test (α = 0.05).

RESULTS

Systemic administration of celecoxib for 7 and 14 days prevented periapical bone resorption (P < 0.0001), differently from indomethacin that exacerbated bone resorption at 7 days (P < 0.0001) or exerted no effect at 14 days (P = 0.8488). Celecoxib treatment reduced osteoclast formation in apical periodontitis, regardless of the period of treatment (P < 0.0001 for 7 days and P = 0.026 for 14 days). Administration of celecoxib or indomethacin differentially modulated the expression of genes involved in bone resorption. At 7 days, celecoxib and indomethacin treatment significantly inhibited expression of mRNA for cathepsin K (P = 0.0005 and P = 0.016, respectively) without changing TRAP, MMP-9 and calcitonin receptor gene expression. At 14 days, celecoxib significantly inhibited expression of mRNA for MMP-9 (P < 0.0001) and calcitonin receptor (P = 0.004), whilst indomethacin exerted no effect on MMP-9 (P = 0.216) and calcitonin receptor (P = 0.971) but significantly augmented cathepsin K gene expression (P = 0.001).

CONCLUSIONS

The selective COX-2 inhibitor celecoxib reduced osteoclastogenic signalling and activity that dampened bone resorption in LPS-induced apical periodontitis in mice, with greater efficacy than the nonselective inhibitor indomethacin.

Effect of non-steroidal anti-inflammatory drugs on pulpal and periapical inflammation induced by lipopolysaccharide

OBJECTIVES

The objective of this study was to evaluate the effect of non-steroidal anti-inflammatory drugs (NSAIDs) in controlling pulpal and periapical inflammation in vivo as a potential coadjutant systemic therapy for pulpitis.

MATERIALS AND METHODS

A suspension containing E. coli lipopolysaccharide (LPS; 1.0 μg/μL) was inoculated into the pulp chamber of the first molars of C57BL/6 mice (n = 72), and the animals were treated daily with indomethacin or celecoxib throughout the experimental periods. After 7, 14, 21, and 28 days, the tissues were removed for histopathological, histoenzymology, histometric, and immunohistochemical evaluation.

RESULTS

Inoculation of LPS into the pulp chamber induced the synthesis of the enzyme cyclooxygenase-2 (COX-2) in dental pulp and periapical region. Indomethacin and celecoxib treatment changed the profile of inflammatory cells recruited to dental pulp and to the periapex, which was characterized by a higher mononuclear cell infiltrate, compared to LPS inoculation alone which recruited a higher amount of polymorphonuclear neutrophils. Administration of indomethacin for 28 days resulted in the development of apical periodontitis and increased osteoclast recruitment, unlike celecoxib.

CONCLUSIONS

NSAIDs indomethacin and celecoxib changed the recruitment of inflammatory cells to a mononuclear profile upon inoculation of LPS into the pup chamber, but indomethacin enhanced periapical bone loss whereas celecoxib did not.

CLINICAL RELEVANCE

Celecoxib, a selective COX-2 inhibitor, can change the profile of inflammatory cells recruited to the dental pulp challenged with LPS and might a be potential systemic coadjutant for treatment of pulpitis.

Panax ginseng Fruit Has Anti-Inflammatory Effect and Induces Osteogenic Differentiation by Regulating Nrf2/HO-1 Signaling Pathway in In Vitro and In Vivo Models of Periodontitis

Periodontitis is an infectious inflammatory disease of tissues around teeth that destroys connective tissues and is characterized by the loss of periodontal ligaments and alveolar bone. A new treatment strategy is needed owing to the limitations of the current surgical treatment method and the side effects of anti-inflammatory drugs. Therefore, here, we assessed whether Panax ginseng fruit extract (PGFE) is a new therapeutic agent for periodontitis in vitro and in vivo. According to the results, PGFE suppressed pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin (IL)-1β, and IL-6, and pro-inflammatory mediators such as inducible nitric oxide synthase and cyclooxygenase-2 through heme oxygenase-1 expression in human periodontal ligament cells stimulated with Porphyromonas gingivalis lipopolysaccharide (PG-LPS). In addition, the osteogenic induction of human periodontal ligament cells was inhibited by PG-LPS, and protein and mRNA levels of osteogenic markers such as alkaline phosphatase, collagen type 1 (COL1), osteopontin (OPN), and runt-related transcription factor 2 (RUNX2) were increased. The efficacy of PGFE for inhibiting periodontitis in vitro was demonstrated in a representative in vitro model of periodontitis induced by ligature and PG-LPS. Subsequently, hematoxylin and eosin staining and micro-computed tomography of the euthanized experimental animal model confirmed suppressed periodontal inflammation, which is an important strategy for treating periodontitis and for recovering the resulting alveolar bone loss. Therefore, PGFE is a potential, novel therapeutic agent for periodontal diseases.

Current understanding of periodontal disease pathogenesis and targets for host-modulation therapy

Recent advances indicate that periodontitis is driven by reciprocally reinforced interactions between a dysbiotic microbiome and dysregulated inflammation. Inflammation is not only a consequence of dysbiosis but, via mediating tissue dysfunction and damage, fuels further growth of selectively dysbiotic communities of bacteria (inflammophiles), thereby generating a self-sustained feed-forward loop that perpetuates the disease. These considerations provide a strong rationale for developing adjunctive host-modulation therapies for the treatment of periodontitis. Such host-modulation approaches aim to inhibit harmful inflammation and promote its resolution or to interfere directly with downstream effectors of connective tissue and bone destruction. This paper reviews diverse strategies targeted to modulate the host periodontal response and discusses their mechanisms of action, perceived safety, and potential for clinical application.

Platelet rich fibrin versus ozone gel for periodontal regeneration in induced rats' intrabony three-wall periodontal defects

BACKGROUND

The question of whether platelet rich fibrin and ozone can enhance regeneration of periodontal defect was addressed.

MATERIALS AND METHODS

three-wall periodontal defects were surgically created in 30 rats involving mesial aspect of right mandibular first molar. Rats were randomly assigned into three groups: 1) Group I (Positive control group). 2) Group II (Ozone treated group) and 3) Group III (PRF treated group). Two weeks after surgery, five rats from each group were euthanized and the remaining was euthanized 4 weeks post surgery. The degree of periodontal regeneration was evaluated using light microscope and scanning electron microscope. Histomorphometric measurements and anti-PCNA immunohistochemical counting were statistically analyzed.

RESULTS

group I showed intense inflammatory reaction with mild new bone formation. In group II, partial regeneration was seen with moderate new woven bone formation in 2 weeks period. After 4 weeks, almost complete restoration of periodontium was seen. In group III, after 2 weeks, moderate lamellar bone formation was observed. In 4 weeks period, the periodontal regeneration was almost completed. Histomorphometric analysis showed a significant difference between group I and group II. The difference between group I and group III was significant in 2 weeks and highly significant after 4 weeks. That between group II and group III was nonsignificant in 2 weeks and significant in 4 weeks. Anti-PCNA analysis was nonsignificant between groups.

CONCLUSIONS

both Platelet rich fibrin and ozone can improve histological parameters associated with healing of experimental intrabony periodontal defects in rats with the former being superior.

Chronic consumption of alcohol increases alveolar bone loss

This study evaluated the effects of the chronic consumption of different concentrations of alcohol on the experimental periodontitis (EP). 160 rats were divided into 4 groups: (EP-NT) rats with EP and no alcohol exposure; (EP-A14) rats with EP exposed to 14% alcohol; (EP-A25) rats with EP exposed to 25% alcohol; (EP-A36) rats with EP exposed to 36% alcohol. The animals from the EP-A14, EP-A25 and EP-A36 groups were subjected to different concentrations of alcohol 30 days before EP induction. The histological characteristics, percentage of bone in the furcation (PBF) and bone metabolism in the furcation region were evaluated. The PBF and tartrate-resistant acid phosphatase (TRAP) data were subjected to statistical analysis. The EP-A14, EP-A25 and EP-A36 groups had lower PBFs compared with the EP-NT group. A more severe inflammatory process and a greater number of TRAP+ cells were also observed. In the EP-A14, EP-A25 and EP-A36 groups, the inflammatory process became more severe as the ingested alcoholic concentration increased. An increase in RANKL immunolabeling and a significantly higher number of TRAP+ cells were also observed. We conclude that chronic alcohol consumption increases the severity of experimental periodontitis in a dose-dependent manner by increasing the magnitude of local inflammatory responses and stimulating alveolar bone resorption.

Meloxicam-loaded solvent exchange-induced in situ forming beta-cyclodextrin gel and microparticle for periodontal pocket delivery

The in situ forming system has attracted attention for periodontitis treatment owing to its sustainable drug release localisation at a periodontal pocket. Given its low aqueous solubility, beta-cyclodextrin (β-CD) may serve as a matrix former of solvent exchange-induced in situ forming gel (ISG) and microparticle (ISM). Meloxicam (Mex)-loaded-β-CD ISG and ISM were prepared using β-CD in dimethyl sulphoxide (ISG) as the internal phase and camellia oil comprising 5% glyceryl monostearate as the external phase (ISM). Mex-loaded β-CD systems comprising 40% β-CD were easily injected via a 24-gauge needle. During solvent exchange with phosphate buffer saline (pH 6.8), the highly concentrated β-CD ISG promoted the phase inversion of β-CD aggregates into matrix-like. Upon exposure to aqueous phase, the ISM system comprising 40% β-CD transformed into microparticles and extended the drug release to 7 days with minimised initial burst release following Fickian diffusion. Moreover, the potential degradability was evident from the high weight loss. High maximum deformation force with high viscous character initiated the slow diffusion rate of the solvent from the ISM system. Therefore, 40% β-CD ISM is a potential local Mex-controlled release system of anti-inflammatory drug for periodontitis treatment.

Drinking green tea alleviates alveolar bone resorption in ligature-induced periodontitis in mice

OBJECTIVES

It has been reported that green tea exerts antibacterial, anti-inflammatory, and antioxidant effects. The purpose of the present study was to evaluate the effects of drinking green tea on bone resorption in ligature-induced periodontitis in mice.

METHODS

Sixty C57BL/6 eight-week-old male mice were used. To induce periodontitis, a ligature was placed for 7 days around the upper left second maxillary molar. After ligature removal, the animals were administered different concentrations of green tea (1.5 g/60 mL, 3 g/60 mL, or 6 g/60 mL) or distilled water. At 1 and 2 weeks of administration, the animals were sacrificed and micro-CT images of the maxillae were taken. Next, the depth and area of alveolar bone loss in the buccal and palatal sides were measured. The number of inflammatory cells and osteoclasts in histological sections were counted.

RESULTS

The result showed ligature-induced alveolar bone loss. Green tea inhibited ligature-induced bone loss in the buccal side in a dose-dependent manner. Histologically, ligature increased the number of inflammatory cells and osteoclasts, but this effect was alleviated by green tea.

CONCLUSIONS

Evidence from this animal experiment suggested that drinking green tea would be potentially beneficial to reduce alveolar bone loss in ligature-induced periodontitis.

Cardiovascular and Autonomic Dysfunction in Murine Ligature-Induced Periodontitis

The present study examined the hemodynamics [arterial pressure (AP), AP variability (APV), heart rate (HR), and heart rate variability (HRV)], cardiac function (echocardiographycally), and myocardial inflammation in Balb/c mice submitted to Periodontitis, through the ligation of the left first molar, or Sham surgical procedure. The first protocol indicated that the AP was similar (136 ± 2 vs. 132 ± 3 mmHg in Sham), while the HR was higher in mice with Periodontitis (475 ± 20 vs. 412 ± 18 bpm in Sham), compared to their Sham counterparts. The APV was higher in mice with Periodontitis when evaluated in the time domain (4.5 ± 0.3 vs. 3.4 ± 0.2 mmHg in Sham), frequency domain (power of the LF band of systolic AP), or through symbolic analysis (patterns 0V + 1V), indicating a sympathetic overactivity. The HRV was similar in the mice with Periodontitis, as compared to their Sham counterparts. In the second protocol, the mice with Periodontitis showed decreased cardiac output (10 ± 0.8 vs. 15 ± 1.4 mL/min in Sham) and ejection fraction (37 ± 3 vs. 47 ± 2% in Sham) associated with increased myocardial cytokines (Interleukin-17, Interleukin-6, and Interleukin-4). This study shows that experimental Periodontitis caused cardiac dysfunction, increased heart cytokines, and sympathetic overactivity, in line with epidemiological studies indicating an increased risk of cardiovascular events in clinical Periodontitis.

Fish oil diet effects on alveolar bone loss, in hypercholesterolemic rats

This study evaluated the effects of replacing a saturated fat diet by n-3 polyunsaturated fatty acids (n-3PUFA), on alveolar bone loss in hypercholesterolemic rats with experimental periodontitis (PD).

METHODS

Eight week old Wistar rats were assigned according to dietary intake. Control group (C, n = 15) fed a commercial diet throughout the experiment. Atherogenic group (AT, n = 30) fed AT diet for 3 weeks; thereafter, AT was randomized to receive either a n-3PUFA (n = 15) or to continue with AT (n = 15) diet. Subsequently, PD was induced in all groups by unilateral ligature (L) of the first molar (M1) of the left mandible, non-ligated contralateral molars served as controls. After every week of PD induction, 5 rats per group were euthanized. Serum was collected for lipids assays and hemi-mandibles were subjected to histomorphometric (% upper and lower interradicular bone volume and periodontal ligament height, hPDL) and radiographic analyses (periodontal bone support, PBS, in ligated teeth, between M1-M2).

RESULTS

Rats fed n-3PUFA diet rapidly induced a significant reduction in the serum lipids (p < 0.001). In all rats the ligated teeth showed a greater bone loss as compared with the unligated molars. At the end of the experiment the AT + L was the worst in % lower bone volume (p < 0.01), hPDL and PBS (p < 0.05). In contrast, rats fed n-3PUFA + L was similar to those rats fed C diet (p > 0.05).

CONCLUSION

Alveolar bone and dyslipidemia improved by substituting saturated fat intake for a n-3PUFA rich diet, in hypercholesterolemic rats with PD.

Protective effect of Platymiscium floribundum Vog. in tree extract on periodontitis inflammation in rats

Periodontitis is an immuno-inflammatory disease, which can lead to tooth loss. This study aimed to investigate the efficacy of Platymiscium floribundum Vog., a Brazilian tree which has been used in folk medicine as an anti-inflammatory agent, in a pre-clinical trial of periodontitis in rats. Periodontitis was induced by placing a sterilized nylon (3.0) thread ligature around the cervix of the second left upper molar of the rats, which received (per os) P. floribundum extract (0.1, 1 or 10 mg/kg) or vehicle 1h before periodontitis-challenge and once daily during 11 days. Treatment with P. floribundum (10mg/kg) decreased alveolar bone loss, MPO activity nitrite/nitrate levels, oxidative stress, TNF-α, IL1-β, IL-8/CINC-1, and PGE2 gingival levels, and transcription of TNF-α, IL1-β, COX-2, iNOS, RANK, and RANKL genes, while elevated both BALP serum levels and IL-10 gingival levels. The animals did not show signs of toxicity throughout the experimental course. These findings show that P. floribundum has anti-inflammatory and anti-resorptive properties in a pre-clinical trial of periodontitis, representing an interesting biotechnological tool.

An alternative, easy and reproducible method of stabilization and ligature-induced periodontitis in mouse

Periodontal disease is one of the most common causes of tooth loss in the world. Ligature-induced is the most used method to study periodontitis. Here, we describe a alternative, easy and accessible experimental technique of ligation in mice. Twenty C57BL/6 female mice were divided in two groups, control and ligation. Ligature group (n = 10) was immobilized in a well described stabilization board and ligature was performed at the first molar using a new procedure here described in detail. Eight weeks later animals were euthanized, and periodontitis hallmarks were evaluated. Ligatures remained attached to the teeth in all animal during the hole experiment. The procedure induced a temporary loss of weight but no causalities or tooth loss. The animals affected by ligation in their molar teeth presented all periodontitis hallmarks, including alveolar bone loss, gingival retraction and inflammatory infiltrate in the studied region both macro and microscopically. The alternative method is low cost, easily reproducible, and induces all periodontitis hallmarks that are sustained until 8 weeks after placement. •Ligature-induced periodontitis in mouse is a powerful tool of research.•Methods describing the procedure in literature are difficult to reproduce.•A alternative stabilization and ligation procedure in mice is completely described here.

Periodontitis and diabetes interrelationships in rats: biochemical and histopathological variables

BACKGROUND

A two-way relationship between diabetes and periodontitis is now clinically established. Both conditions share common mechanisms of pathogenesis that are related to altered immune-inflammatory responses at local and/or systemic levels. The aim of this study is to investigate whether periodontitis is associated with the development and progression of diabetes and to evaluate the health impact of coexistence of both diseases.

MATERIAL AND METHODS

Male Sprague Dawley rats (10 weeks old) were randomized into seven groups (n = 12): Group 1) Control; Groups 2 and 6) Periodontitis induced at two or six weeks; Groups 3 and 5) Diabetes induced at two or six weeks; Groups 4 and 7) Periodontitis followed by diabetes, and diabetes followed by periodontitis at two or six weeks. For diabetes induction, animals received a one-time intravenous injection of streptozotocin (50 mg/kg). Periodontitis was induced by Lipoppolysaccharide injection (20 μg/rat) through the palatal gingival and by placing a ligature of 0/0 braided silk around the cervix of the upper right second molar. Body weight, glycaemia as well as urine were collected weekly. Rats were sacrificed at the end of week 10, gingival tissue was removed, fixed in formaldehyde and processed for histopathological study.

RESULTS

Body weight was significantly decreased (25%) following diabetes induction (p < 0.01). 40% weight loss was observed when diabetes was induced first compared to 30% when periodontitis was first induced in the animals (p < 0.01). Rats treated with streptozotocin showed a three-fold increase in diabetes compared to the control group (p < 0.01). In rats where periodontitis was induced after diabetes, glucose levels increased significantly (450 mg/dL) compared to glucose levels (410 mg/dL) where periodontitis was induced first (p < 0.01). Histopathological studies showed greater alveolar bone loss when both diabetes and periodontitis were present.

CONCLUSION

When periodontitis occurs after diabetes it aggravates the symptoms of the two pathologies. When diabetes is induced after periodontitis, no symptoms aggravation is observed for diabetes, although periodontitis gets worse.

Strontium Ranelate Elevates Expression of Heme Oxygenase-1 and Decreases Alveolar Bone Loss in Rats

Objectives

The purpose of this study was to determine the effects of strontium ranelate on ligature-induced periodontitis in rats and assess the putative involvement of heme oxygenase-1 (HO-1) pathway in these effects.

Material and Methods

Male Wistar rats underwent nylon ligature placement around maxillary molars and were treated (v.o.) with strontium ranelate (20 or 100 mg/kg) for 7 days. After that, rats were euthanized and histomorphometric/histopathological analyses and RT-PCR for HO-1 expression were performed.

Results

Strontium ranelate (20 or 100 mg/kg) prevented bone resorption by 28% and 38%, respectively. Strontium ranelate treatment (100 mg/kg) up-regulated (P < 0.05) heme oxygenase-1 mRNA levels in the gingival tissues in comparison to control groups.

Conclusions

Strontium ranelate prevented periodontal bone loss in experimental periodontitis in rats while heme oxygenase-1 mRNA levels increased after treatment.

Aminothiazoles inhibit osteoclastogenesis and PGE2 production in LPS-stimulated co-cultures of periodontal ligament and RAW 264.7 cells, and RANKL-mediated osteoclastogenesis and bone resorption in PBMCs

Inflammatory mediator prostaglandin E₂ (PGE₂ ) contributes to bone resorption in several inflammatory conditions including periodontitis. The terminal enzyme, microsomal prostaglandin E synthase-1 (mPGES-1) regulating PGE₂ synthesis is a promising therapeutic target to reduce inflammatory bone loss. The aim of this study was to investigate effects of mPGES-1 inhibitors, aminothiazoles TH-848 and TH-644, on PGE₂ production and osteoclastogenesis in co-cultures of periodontal ligament (PDL) and osteoclast progenitor cells RAW 264.7, stimulated by lipopolysaccharide (LPS), and bone resorption in RANKL-mediated peripheral blood mononuclear cells (PBMCs). PDL and RAW 264.7 cells were cultured separately or co-cultured and treated with LPS alone or in combination with aminothiazoles. Multinucleated cells stained positively for tartrate-resistant acid phosphatase (TRAP) were scored as osteoclast-like cells. Levels of PGE₂ , osteoprotegerin (OPG) and interleukin-6, as well as mRNA expression of mPGES-1, OPG and RANKL were analysed in PDL cells. PBMCs were treated with RANKL alone or in combination with aminothiazoles. TRAP-positive multinucleated cells were analysed and bone resorption was measured by the CTX-I assay. Aminothiazoles reduced LPS-stimulated osteoclast-like cell formation both in co-cultures and in RAW 264.7 cells. Additionally, aminothiazoles inhibited PGE₂ production in LPS-stimulated cultures, but did not affect LPS-induced mPGES-1, OPG or RANKL mRNA expression in PDL cells. In PBMCs, inhibitors decreased both osteoclast differentiation and bone resorption. In conclusion, aminothiazoles reduced the formation of osteoclast-like cells and decreased the production of PGE₂ in co-cultures as well as single-cell cultures. Furthermore, these compounds inhibited RANKL-induced bone resorption and differentiation of PBMCs, suggesting these inhibitors for future treatment of inflammatory bone loss such as periodontitis.

Tocoyena sellowiana extract decreases bone loss in an experimental model of periodontitis in rats: Putative role for cyclooxygenase-2 and IL-1? inhibition

Tocoyena sellowiana (Cham. & Schltdl.) K.Schum is one of the most important families of Brazilian medicinal plants. This study aimed to evaluate the effect of Tocoyena sellowiana (Cham. & Schltdl.) K.Schum ethanolic extract in a pre-clinical trial of periodontitis and to investigate possible mechanisms underlying such effects. Periodontitis was induced in Wistar rats by placing a nylon thread ligature around second upper left molars for 11 days. Rats received (per os) Tocoyena sellowiana (0.1, 1 or 10?mg?kg) or vehicle 1?h before ligature and daily until day 11. Macroscopic, histopathological, and COX-2 immunohistochemical analyses were performed to evaluate the periodontium. The gingival tissue was used to quantify the myeloperoxidase (MPO) activity and interleukin (IL)-1? levels by ELISA. Blood samples were collected to evaluate bone-specific alkaline phosphatase (BALP), the dosage of creatinine, aspartate and alanine transaminases. The liver, kidneys, spleen, and body mass variations were also evaluated. Tocoyena sellowiana decreased bone loss, reduced MPO, IL-1? levels as well as COX-2 immunostaining, and increased BALP activity. Moreover, Tocoyena sellowiana did not alter organs nor body weight. Tocoyena sellowiana reduced bone loss in rats and its efficacy was at least partially dependent upon both IL-1? and cyclooxygenase-2 inhibition.

Anti-inflammatory effect of ATB-352, a H2S -releasing ketoprofen derivative, on lipopolysaccharide-induced periodontitis in rats

Periodontal disease is the most common cause of tooth loss in humans, is an inflammatory disease initiated by oral microbial biofilm. Given the involvement of the inflammatory pathway in this type of pathology, the main pharmacological strategy for the treatment of periodontitis, is the inhibition of the inflammatory process in order to prevent tissue destruction and bone resorption, a condition associated with a painful state. To do this, the best class of drugs are Non-steroidal anti-inflammatory drugs (NSAIDs), however, the presence of side effects, especially at the gastrointestinal tract, limits their use for long-term therapy. Recently, some evidence shows that derivatives of NSAIDs capable of releasing hydrogen sulphide exhibit lower collateral effects, particularly at the gastric level. In fact, H2S is an endogenous gaseous mediator with a cytoprotective role at the gastric level. In this study, we have compared the protective effects of ketoprofen with ATB-352, a hydrogen sulfide-releasing derivative of ketoprofen, in an experimental model of periodontitis in rat. Periodontitis was induced by a single intragingival injection of 1 μl LPS (10 μg/μl), Our results show that 14 h after intragingival injection of LPS, there was a high tissue damage associated with bone resorption, and in gingivomucosal tissues there was a significant expression of NF-kb p65 and pro-inflammatory cytokine as well as a higher expression of COX-2 and iNOS, activation of the apoptotic process, and also increased levels of NGF expression, often associated with a higher nociceptive perception. Treatment with ATB-352 at the dose of 20mg\kg, was able to reduce the inflammatory process associated with intragingival LPS injection and also had a positive effect on bone resorption and tissue damage.

Inhibition of 5-lipoxygenase attenuates inflammation and BONE resorption in lipopolysaccharide-induced periodontal disease

BACKGROUND

Arachidonate-5-lipoxygenase (5-LO) activity and increased leukotriene B4 (LTB4) production have been implicated in various inflammatory conditions. Increased production of leukotrienes has been associated with periodontal diseases; however, their relative contribution to tissue destruction is unknown. In this study, an orally active specific 5-LO inhibitor is used to assess its role in inflammation and bone resorption in a murine model of lipopolysaccharide (LPS)-induced periodontal disease.

METHODS

Periodontal disease was induced in Balb/c mice by direct injections of LPS into the palatal gingival tissues adjacent to the maxillary first molars three times per week for 4 weeks. Animals were treated with biochemical inhibitor (2 mg/kg/daily) or the same volume of the vehicle by oral gavage. Microcomputed tomography analysis was used to assess bone resorption. Enzyme immunoassay determined LTB4, and enzyme-linked immunosorbent assays quantified tumor necrosis factor (TNF), interleukin (IL)-12, and IL-10 in gingival tissues. Histologic sections were used for the morphometric analysis (number of neutrophils and mononuclear cells). Osteoclasts were counted in tartrate-resistant acid phosphatase-stained sections.

RESULTS

Administration of 5-LO inhibitor effectively reduced production of LTB4 (23.7% decrease) and significantly reduced TNF and IL-12 levels in gingival tissues. Moreover, reduction of LTB4 levels in gingival tissues was associated with a significant decrease in bone resorption and a marked reduction in number of osteoclasts and inflammatory cells.

CONCLUSION

5-LO activity plays a relevant role in inflammation and bone resorption associated with the LPS model of experimental periodontal disease.

Stemodia maritima L. Extract Decreases Inflammation, Oxidative Stress, and Alveolar Bone Loss in an Experimental Periodontitis Rat Model

Periodontitis is very prevalent worldwide and is one of the major causes of tooth loss in adults. About 80% of the worldwide population use medicinal plants for their health care. Stemodia maritima L. (S. maritima) antioxidant and antimicrobial effects in vitro as well as anti-inflammatory properties. Herein, the potential therapeutic effect of S. maritima was assessed in rats subjected to experimental periodontitis (EP). EP was induced in female Wistar rats by nylon thread ligature around 2nd upper left molars for 11 days. Animals received (per os) S. maritima (0.2; 1 or 5 mg/kg) or vehicle (saline + DMSO) 1 h before ligature and then once daily for 11 days. The naive group had no manipulation. After this time-point, the animals were terminally anesthetized, and the maxillae were removed for morphometric and histological analyzes (HE). Gingival tissues were dissected to cytokine levels detection (TNF-α, IL1-β, CINC-1, and IL-10), enzymes superoxide dismutase (SOD), and catalase (CAT) analysis, as well as gene expression (TNF-α, IL-1β, RANK, and iNOS) by qRT-PCR. Systemic parameters (weight variation, plasma levels of hepatic enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT), creatinine, total alkaline phosphatase (TALP), and bone alkaline phosphatase (BALP) were performed. Histological analysis of the stomach, liver, kidney, and heart was also performed. S. maritima (5 mg/kg) decreased alveolar bone loss, TNF-α and CINC-1 gingival levels, oxidative stress, and transcription of TNF-α, IL1-β, RANK, and iNOS genes. It elevated both BALP activity and IL-10 gingival levels. The animals showed no any signs of toxicity. In conclusion, S. maritima reduced pro-inflammatory cytokine production, oxidative stress, and alveolar bone loss in a pre-clinical trial of periodontitis. S. maritima is a potential tool for controlling the development of periodontitis.

Selective COX-2 Inhibitor (Meloxicam) and Tooth-Supporting Bone Quality. A Histomorphometric Study in Rats

Abstract The effects of the non-steroidal anti-inflammatory drugs (NSAIDs) on bone quantity and quality were investigated for years. However, there is lack of information on the impact of NSAIDs on the quality of tooth-supporting alveolar bone in absence of periodontal inflammation. Thus, the aim of this study was to evaluate histometrically the influence of a selective COX-2 NSAID (Meloxicam) on the inter-radicular bone mineral density in rats. Forty-nine adult male Wistar rats were randomly divided into four experimental groups: Subcutaneous injection of 0.9% sterile saline for 15 days (G1; n=12) and 45 days (G2; n=11); and subcutaneous injection of Meloxicam for 15 days (G3; n=13) and 45 days (G4; n=13). Mineral density was histometrically determined in the inter-radicular area of the 1st mandibular molars and data analysis performed by two-way ANOVA (a=5%). Results showed no interaction between time and treatment (p>0.05) and that meloxicam did not affect the alveolar bone density. In contrast, it was found that inter-radicular alveolar bone density increased with time (91.88±3.08% and 92.86±2.38% for groups 15 and 45 days, respectively) (p<0.05). Within the limits of this study, daily administration of a selective COX-2 inhibitor (Meloxicam) did not affect the quality of the inter-radicular alveolar bone in absence of periodontal infection.

Effects of glucocorticoid-induced osteoporosis on bone tissue of rats with experimental periodontitis

OBJECTIVE

To evaluate the effects of osteoporosis induced by glucocorticoid (GIOP) on bone tissue of rats with experimental periodontitis (EP).

DESIGN

48 male Wistar rats divided into groups: Naïve, EP, GIOP and GIOP+EP. Rats of GIOP and GIOP+EP groups received 7mg/kg of dexamethasone intramuscularly once a week for 5 weeks. Following, EP and GIOP+EP groups were subjected to ligature-induced periodontitis. Naïve group experienced no manipulation. After 11 days, the animals were euthanized and left maxillae collected for macroscopic, radiographic, micro-tomographic and microscopic analysis of alveolar bone loss (ABL). Blood samples were collected for determination of bone-specific alkaline phosphatase (BALP) levels and the right femurs were removed for radiographic and biomechanical analysis.

RESULTS

EP caused ABL and reduced BALP levels (p<0,05), but it did not change the architecture or biomechanics of femur, compared to Naïve. GIOP did not cause ABL, but it significantly decreased alveolar bone mineral density (ABMD), bone percentage and trabecular thickness (Tb.Th) and increased alveolar bone porosity (p<0.05) and significantly reduced BALP serum levels, as well as radiographic density and Young's module of femur, compared to Naïve. There was a greater ABL in group GIOP+EP when compared to EP (p<0.05). GIOP+EP caused a greater decrease on ABMD, Tb.Th, bone percentage and increased bone porosity (p<0.05) and also presented a significant reduction in BALP levels (p<0.05), in radiographic density and in Young's module of femur compared to EP (p<0.05).

CONCLUSIONS

GIOP can potentiate the destructive effects of EP on alveolar bone and alter the systemic bone loss, by promoting bone resorption and reducing osteoblast activity.

Meloxicam medication reduces orthodontically induced dental root resorption and tooth movement velocity: a combined in vivo and in vitro study of dental-periodontal cells and tissue

Non-steroidal anti-inflammatory drugs (NSAID) are used to alleviate pain sensations during orthodontic therapy but are also assumed to interfere with associated pseudo-inflammatory reactions. In particular, the effects of partially selective COX-2 inhibition over the constitutively expressed COX-1 (11:1) on periodontal cells and tissue, as induced by the NSAID meloxicam, remain unclear. We investigate possible adverse side-effects and potentially useful beneficial effects during orthodontic therapy and examine underlying cellular and tissue reactions. We randomly assigned 63 male Fischer344 rats to three consecutive experiments of 21 animals each (cone-beam computed tomography; histology/serology; reverse-transcription quantitative real-time polymerase chain reaction) in three experimental groups (n = 7; control; orthodontic tooth movement [OTM] of the first/second upper left molars [NiTi coil spring, 0.25 N]; OTM with a daily oral meloxicam dose of 3 mg/kg). In vitro, we stimulated human periodontal ligament fibroblasts (hPDL) with orthodontic pressure (2 g/cm²) with/without meloxicam (10 μM). In vivo, meloxicam significantly reduced serum C-reactive protein concentration, tooth movement velocity, orthodontically induced dentine root resorption (OIRR), osteoclast activity and the relative expression of inflammatory/osteoclast marker genes within the dental-periodontal tissue, while presenting good gastric tolerance. In vitro, we observed a corresponding significant decrease of prostaglandin E₂/interleukin-6/RANKL(-OPG) expression and of hPDL-mediated osteoclastogenesis. By inhibiting prostaglandin synthesis, meloxicam seems to downregulate hPDL-mediated inflammation, RANKL-induced osteoclastogenesis and, consequently, tooth movement velocity by about 50%, thus limiting its suitability for analgesia during orthodontic therapy. However, its protective effects regarding OIRR and good tolerance profile suggest future prophylactic application, which merits its further investigation.

Novel meloxicam releasing electrospun polymer/ceramic reinforced biodegradable membranes for periodontal regeneration applications

Periodontal disease is associated with the destruction of periodontal tissues, along with other disorders/problems including inflammation of tissues and severe pain. This paper reports the synthesis of meloxicam (MX) immobilized biodegradable chitosan (CS)/poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) based electrospun (e-spun) fibers and films. Electrospinning was employed to produce drug loaded fibrous mats, whereas films were generated by solvent casting method. In-vitro drug release from materials containing varying concentrations of MX revealed that the scaffolds containing higher amount of drug showed comparatively faster release. During initial first few hours fast release was noted from membranes and films; however after around 5h sustained release was achieved. The hydrogels showed good swelling property, which is highly desired for soft tissue engineered implants. To investigate the biocompatibility of our synthesized materials, VERO cells (epithelial cells) were selected and cell culture results showed that these all materials were non-cytotoxic and also these cells were very well proliferated on these synthesized scaffolds. These properties along with the anti-inflammatory potential of our fabricated materials suggest their effective utilization in periodontital treatments.

Omega-3 fatty acids as an adjunct for periodontal therapy-a review

OBJECTIVES

The aim of this article is to present an overview of omega-3 fatty acids, their anti-inflammatory properties and potential use as an adjunct for periodontal therapy.

MATERIALS AND METHODS

A general literature search was conducted to provide an overview of omega-3 fatty acids, their metabolism and anti-inflammatory properties. A more specific literature search of PubMed and EMBASE was conducted to identify articles dealing studies investigating the effects of omega-3 fatty acids in the treatment of periodontitis in animals and humans and included cross-sectional, longitudinal and intervention designs.

RESULTS

To date, there is good emerging evidence that dietary supplementation with fish oil may be of some benefit and this is enhanced if combined with aspirin. All clinical intervention studies to date have been on small sample sizes, and this indicates there is need for larger and more robust clinical trials to verify these initial findings.

CONCLUSIONS

Dietary supplementation with fish oil could be a cost-effective adjunctive therapy to the management of periodontal disease.

CLINICAL RELEVANCE

The host modulatory properties of omega-3 fatty acids warrant further assessment of their use as an adjunct in the management of periodontitis.

Dry Extract of Matricaria recutita L. (Chamomile) Prevents Ligature-Induced Alveolar Bone Resorption in Rats via Inhibition of Tumor Necrosis Factor-α and Interleukin-1β

BACKGROUND

Matricaria recutita L. (chamomile) has demonstrated anti-inflammatory activity. Accordingly, the ability of the Matricaria recutita extract (MRE) to inhibit proinflammatory cytokines and its influence on alveolar bone resorption (ABR) in rats.

METHODS

Wistar rats were subjected to ABR by ligature with nylon thread in the second upper-left molar, with contralateral hemiarcade as control. Rats received polysorbate TW80 (vehicle) or MRE (10, 30, and 90 mg/kg) 1 hour before ligature and daily until day 11. The periodontium was analyzed by macroscopy, histometry, histopathology, and immunohistochemistry for the receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OPG), and tartrate-resistant acid phosphatase (TRAP). The gingival tissue was used to quantify the myeloperoxidase (MPO) activity and tumor necrosis factor (TNF)-α and interleukin (IL)-1β levels by enzyme-linked immunosorbent assay. Blood samples were collected to evaluate bone-specific alkaline phosphatase (BALP), leukogram, and dosages of aspartate and alanine transaminases, urea, and creatinine. Aspects of liver, kidneys, spleen, and body mass variations were also evaluated.

RESULTS

The 11 days of ligature induced bone resorption, low levels of BALP, leukocyte infiltration; increase of MPO, TNF-α, and IL-1β; immunostaining increase for RANKL and TRAP; reduction of OPG and leukocytosis, which were significantly prevented by MRE, except for the low levels of BALP and the leukocytosis. Additionally, MRE did not alter organs or body weights of rats.

CONCLUSION

MRE prevented the inflammation and ABR by reducing TNF-α and IL-1β, preventing the osteoclast activation via the RANKL-OPG axis, without interfering with bone anabolism.

Genistein suppresses Prevotella intermedia lipopolysaccharide-induced inflammatory response in macrophages and attenuates alveolar bone loss in ligature-induced periodontitis

OBJECTIVE

Genistein is a major isoflavone subclass of flavonoids found in soybean and a potent tyrosine kinase inhibitor. The present study aimed to assess the effect of genistein on the production of proinflammatory mediators in murine macrophages stimulated with lipopolysaccharide (LPS) isolated from Prevotella intermedia, a pathogen associated with different forms of periodontal disease, and to evaluate its possible influence on alveolar bone loss in ligature-induced periodontitis using micro-computed tomography (micro-CT) analysis as well.

DESIGN

LPS was isolated from P. intermedia ATCC 25611 by using the standard hot phenol-water method. Culture supernatants were analyzed for nitric oxide (NO) and interleukin-6 (IL-6). Inducible NO synthase (iNOS) protein expression was evaluated by immunoblot analysis. Real-time PCR was carried out to measure iNOS and IL-6 mRNA expression. In addition, effect of genistein on alveolar bone loss was evaluated in a rat model of experimental periodontitis using micro-CT analysis.

RESULTS

Genistein significantly attenuated P. intermedia LPS-induced production of iNOS-derived NO and IL-6 with attendant decrease in their mRNA expression in RAW264.7 cells. In addition, when genistein was administered to rats, decreases in alveolar bone height and bone volume fraction induced by ligature placement were significantly inhibited. Genistein administration also prevented ligature-induced alterations in the microstructural parameters of trabecular bone, including trabecular thickness, trabecular separation, bone mineral density and structure model index.

CONCLUSIONS

While additional studies are required, we suggest that genistein could be utilized for the therapy of human periodontitis in the future.

Effect of the probiotic Saccharomyces cerevisiae on ligature-induced periodontitis in rats

BACKGROUND AND OBJECTIVE

This study assessed the effects of the local use of Saccharomyces cerevisiae as monotherapy and as an adjuvant to the mechanical treatment of ligature-induced periodontitis in rats.

MATERIAL AND METHODS

Periodontitis was induced in 72 rats via the installation of a ligature around the mandibular first molar. After 7 d, the ligature was removed and the rats were placed in one of the following groups: no treatment (C; n = 18); scaling and root planing (SRP; n = 18); local irrigation with probiotics (PRO; n = 18); and SRP followed by local irrigation with probiotics (SRP/PRO; n = 18). Six rats from each group were killed at 7, 15 and 30 d. The histological characteristics, alveolar bone loss (ABL) and immunolabeling of tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β), interleukin-10 (IL-10) and TRAP on the furcation area of the first molar were assessed.

RESULTS

The PRO group showed features of acceleration of the tissue-repair process during the entire experiment. On day 15, there was less ABL in the SRP/PRO group compared with the C group. There were fewer TRAP-positive cells in the SRP and SRP/PRO groups at 30 d. There was less immunostaining for TNF-α in the PRO and SRP/PRO groups and less immunostaining for IL-1β in the PRO group. However, there was more immunostaining for IL-10 in the PRO group on day 15.

CONCLUSION

Local use of the probiotic did not result in any adverse effects on periodontal tissues. When used as monotherapy or as an adjuvant, the probiotic was effective at controlling periodontitis in rats.

Comparative study to investigate the effect of meloxicam or minocycline HCl in situ gel system on local treatment of periodontal pockets

In situ gelling formulations allow easy application to the target area. Gelation is induced by physiological stimuli at the site of application where the formula attains semisolid properties and exerts sustained drug release. In situ gelling formulations containing either 3% meloxicam (Mx) or 2% minocycline HCl (MH) were prepared for local application into the periodontal pockets. Gel formulations were based on the thermosensitive Pluronic(®) (Pl) and the pH-sensitive Carbopol(®) (C) polymers. C gels were prepared in combination with HPMC (H) to decrease its acidity. The total percent drug released from Pl formulae was 21.72% after 1 week for Mx and 85% after 3 days for MH. Their release kinetics data indicated anomalous non-Fickian behavior that could be controlled by both diffusion and chain relaxation. Addition of MH to C/H gels (1:2.5) resulted in liquefaction, followed by drug precipitation. Regarding C/H gel containing Mx, it showed a prolonged release rate up to 7 days with an initial burst effect; the kinetics data revealed Fickian-diffusion mechanism. The in vitro antibacterial activity studies for MH gel in Pl revealed that the drug released exceeded the minimum inhibitory concentration (MIC) of MH against Staphylococcus aureus ATCC 6538; placebo gel showed no effect on the microorganism. Clinical evaluation of Pl gels containing either Mx or MH showed significant improvement in chronic periodontitis patients, manifested by decrease in pocket depth and gingival index and increase in bone density.