Effects of Locally Administered Tiludronic Acid on Experimental Periodontitis in Rats

FoxO1 Agonists Promote Bone Regeneration in Periodontitis by Protecting the Osteogenesis of Periodontal Ligament Stem Cells

Protecting the function of periodontal ligament stem cells (PDLSCs) is crucial for bone regeneration in periodontitis. Forkhead box protein O1 (FoxO1) has been previously reported as a crucial mediator in bone homeostasis, providing a favorable environment for osteoblast proliferation and differentiation. In this study, we investigated the effect and mechanism of FoxO1 agonists on the osteogenesis of PDLSCs under inflammatory conditions. In this study, we screened FoxO1 agonists by detecting their effects on the osteogenic differentiation of PDLSCs. Then, the function of these agonists in bone regeneration was analyzed in the periodontitis model. We found that hyperoside or 2-furoyl-LIGRLO-amide trifluoroacetate salt (2-Fly) promoted osteogenic differentiation under inflammation by simultaneously inhibiting nuclear factor κB (NF-κB) activation, β-catenin expression, and reactive oxygen species (ROS) production. Moreover, local injection of hyperoside or 2-Fly rescued the expression of FoxO1 and runt-related transcription factor 2 (Runx2) in vivo, alleviating alveolar bone loss and periodontal ligament damage. These findings suggested that FoxO1 agonists exerted a protective effect on osteogenesis in PDLSCs, as a result, facilitating bone formation under inflammatory conditions. Taken together, FoxO1 might serve as a therapeutic target for bone regeneration in periodontitis by mediating multiple signaling pathways.

A new mixed model of periodontitis-induced preeclampsia: A pilot study

OBJECTIVES/BACKGROUND

Recent studies have shown that periodontal disease is strongly related to gestational complications such as preeclampsia (PE). PE is responsible for 42% of maternal deaths worldwide and kills approximately 76 000 women a year. In addition, children born under PE conditions are at increased risk of hospitalization due to metabolic disorders, epilepsy, and other complications. Numerous reviews and clinical studies on PE have been published, but the mechanisms underlying the relationship between periodontal disease and PE and the way periodontopathogens alter vascular response in pregnant women remain unclear.

METHODS

This study aims to verify whether periodontal disease induces PE by using the association of two periodontitis (PD) models: ligature and oral Porphyromonas gingivalis (P. gingivalis) W83 inoculation in Wistar rats. At gestational day 5, the ligature was placed on each mandibular first molar, which was followed by daily oral P. gingivalis inoculation for 15 days. At gestational day 19, urine was collected, and invasive arterial pressure was measured. The animals were euthanized, and plasma and tissues were collected.

RESULTS

After 15 days of the association of ligature and P. gingivalis inoculation, the animals presented the characteristic symptoms of PE: altered blood pressure, proteinuria, and change in litter size (number of pups) and pup weight when compared to the control group (p < .005). The PE animals also presented greater bone porosity, trabecular separation, and reduced bone volume in the hemimandibles, as well as altered inflammatory response. The level of cytokine IL-6 was higher in the PE group than in the control group (p < .005).

CONCLUSION

The association of two PD models effectively induced PE. To our knowledge, this is the first study on the oral use of P. gingivalis for PE induction. Our results support the importance of PD as a possible cause for PE development, opening an important new avenue to study cause and consequence relationships in inflammation and PE due to exposure to periodontal infection.

Effect of adjuvant bisphosphonates on treatment of periodontitis: Systematic review with meta-analyses

Background

Previous systematic reviews showed additional benefit of adjuvant bisphosphonates (BP) in the treatment of periodontitis. In contrast, it is unclear the effect of BP in patients with diabetes and smokers, its pooled effect when administered locally or systemically is also unknown.

Objectives

This study aimed to systematically review the literature about the use of BP as adjuvant to nonsurgical scaling and root planning (SRP).

Methodology

This study followed the PRISMA guideline. This study included randomized clinical trials that administered locally or systemically BPs as adjuvant for periodontal treatment. Five databases were used. Meta-analyses were performed, using the pooled mean differences (MD) for clinical attachment level (CAL) and probing pocket depth (PPD). Standard mean difference (SMD) was used for radiographic assessment (RADIO). Subgroup analyses were performed for locally delivered meta-analyses, considering diabetes and smoking exposure.

Results

Thirteen studies were included. It was showed MD of 1.52 ​mm (95%CI: 0.97-2.07) and 1.44 ​mm (95%CI: 1.08-1.79) for PPD reduction and CAL gain, respectively, for locally delivered BP. BP was not able to provide significant improvements in smokers (subgroup analysis) when considering CAL (MD: 1.37; 95%CI: -0.17-2.91) and PPD (MD: 1.35; 95%CI: -0.13-2.83). Locally delivered BP also improved significantly the RADIO assessments (SMD: 4.34; 95%CI: 2.94-5.74). MD for systemically administered BP was 0.40 ​mm (95%CI: 0.21-0.60), 0.51 ​mm (95%CI: 0.19-0.83) and 1.05 (95%CI: 0.80-1.31) for PPD, CAL and RADIO, respectively.

Conclusion

The administration of BP in adjunct to SRP may result in additional clinical effects.

Carotid sinus nerve stimulation attenuates alveolar bone loss and inflammation in experimental periodontitis

Baroreceptor and chemoreceptor reflexes modulate inflammatory responses. However, whether these reflexes attenuate periodontal diseases has been poorly examined. Thus, the present study determined the effects of electrical activation of the carotid sinus nerve (CSN) in rats with periodontitis. We hypothesized that activation of the baro and chemoreflexes attenuates alveolar bone loss and the associated inflammatory processes. Electrodes were implanted around the CSN, and bilateral ligation of the first mandibular molar was performed to, respectively, stimulate the CNS and induce periodontitis. The CSN was stimulated daily for 10 min, during nine days, in unanesthetized animals. On the eighth day, a catheter was inserted into the left femoral artery and, in the next day, the arterial pressure was recorded. Effectiveness of the CNS electrical stimulation was confirmed by hypotensive responses, which was followed by the collection of a blood sample, gingival tissue, and jaw. Long-term (9 days) electrical stimulation of the CSN attenuated bone loss and the histological damage around the first molar. In addition, the CSN stimulation also reduced the gingival and plasma pro-inflammatory cytokines induced by periodontitis. Thus, CSN stimulation has a protective effect on the development of periodontal disease mitigating alveolar bone loss and inflammatory processes.

Effects of local administration of tiludronic acid on experimental periodontitis in diabetic rats

BACKGROUND

Tiludronic acid (TIL) presents antiresorptive and anti-inflammatory properties and has not been evaluated in the periodontitis-diabetes mellitus (DM) association to date, to the best knowledge of the authors. This study evaluates effects of local administration of TIL on experimental periodontitis (EP) in rats with streptozotocin-induced DM.

METHODS

Thirty-two animals (Rattus norvegicus albinus, Wistar) were divided into groups DM/C (Control), DM/EP, DM/EP/TIL1, and DM/EP/TIL3. In EP groups, a ligature was placed around mandibular first molars. In groups DM/EP/TIL1 and DM/EP/TIL3, TIL solutions (1 and 3 mg/kg, respectively) were injected into the gingival tissue of mandibular molars every other day for 10 days, until euthanasia. Periodontal tissues were analyzed by microcomputed tomography (micro-CT), histomorphometry, immunohistochemistry (tartrate-resistant acid phosphatase [TRAP], receptor activator of nuclear factor-κB ligand [RANKL], osteoprotegerin, cleaved caspase 3), and quantitative reverse transcription-polymerase chain reaction (interleukin [IL]-1β, vascular endothelial growth factor [VEGF]).

RESULTS

In micro-CT analyses, groups DM/EP/TIL1 and DM/EP/TIL3 presented reduced alveolar bone resorption (P < 0.05). Group DM/EP/TIL3 presented decreased attachment loss (P < 0.05). The amount of TRAP-positive multinucleated cells was decreased in TIL groups (P < 0.05). Group DM/EP/TIL3 presented a lower immunolabeling pattern for RANKL (P < 0.05). TIL treatment decreased genic expression of IL-1β, and in group DM/EP/TIL3, expression of VEGF was increased (P < 0.05).

CONCLUSION

Local administration of TIL promoted a protective effect against tissue destruction in EP in diabetic rats, and the dosage of 3 mg/kg of TIL promoted the best results regarding its antiresorptive and anti-inflammatory effects.

Electroacupuncture increases immunoexpression of CB1 and CB2 receptors in experimental model of inflammatory bone loss

This study evaluated the participation of CB1 and CB2 receptors in the antiresorptive effect of electroacupuncture (EA) on an experimental model of inflammatory bone loss in rats. 30 rats were divided into five groups: C (control); EP (experimental periodontitis); EA (C+ EA); EP-EA (EP+ EA in the acupoints LI4, LG11, ST36, ST44); EP - EA-sham (EP+ EA in sham acupoints). For the EP groups, a ligature was placed around the right mandibular first molars at day 1. Sessions of EA or EA-sham were assigned every other day. Animals were euthanized at day 11. Histometric analysis was performed to evaluate the percentage of bone area in the furcation area. Immunolabeling patterns in the periodontal tissues and immunofluorescent staining in the trigeminal ganglia and in the trigeminal spinal tract for CB1 and CB2 receptors were performed. It was observed increased bone loss in the furcation in the EP and EP-EA-sham groups, in comparison to the other groups (p < 0.05). Enhanced CB2 immunolabeling was observed in the periodontal tissues in the EP-EA group, when compared to the EP and EP-EA-sham groups (p < 0.05). Increased CB1 immunofluorescent staining was observed in the neural tissues in the EA treated group in comparison with the other groups (p < 0.05), while no expression of CB2 was observed in those regions. Our study showed that in the presence of inflammatory bone disease, EA treatment reduced bone erosion and increased the immunoexpression of CB1 in the neural tissues and CB2 in the periodontal tissues.

Effects of leukocyte- and platelet-rich fibrin associated or not with bovine bone graft on the healing of bone defects in rats with osteoporosis induced by ovariectomy

OBJECTIVE

To evaluate the healing of critical size defects (CSDs) in calvaria of rats with osteoporosis induced by ovariectomy and treated with leukocyte- and platelet-rich fibrin (L-PRF) associated or not with bovine bone graft (XENO).

MATERIAL AND METHODS

A total of 32 rats underwent a bilateral ovariectomy procedure. After 3 months, one 5 mm in diameter CSD was created in the middle of the calvaria of each animal. In group C, defect was filled with blood clot only. In PRF, XENO, and PRF-XENO groups, defects were filled with 0.1 ml of L-PRF, 0.1 ml of XENO, and a mixture of 0.1 ml of L-PRF plus 0.1 ml of XENO, respectively. L-PRF compressed clots were used to cover the defects in PRF and PRF-XENO groups. Animals were submitted to euthanasia at 30 postoperative days. Histomorphometric, microtomographic, and immunohistochemical analyses were performed.

RESULTS

PRF-XENO group presented greater amount of neoformed bone (NB) when compared with XENO group, as well as higher expression of vascular endothelial growth factor (VEGF), osteocalcin (OCN), and bone morphogenetic protein (BMP-2/4) (p < .05). PRF group presented increased amount of NB and higher expression of VEGF, OCN, BMP-2/4, and Runt-related transcription factor 2 (RUNX-2) when compared with group C (p < .05).

CONCLUSIONS

(a) The isolated use of L-PRF clot can improve bone neoformation in CSDs in rats with osteoporosis induced by ovariectomy, but seems to lead to decreased amount of bone neoformation when compared to the isolated use of XENO; (b) L-PRF potentiates the healing of XENO in rats with osteoporosis induced by ovariectomy.

Effects of local application of alendronate on early healing of extraction socket in dogs

OBJECTIVE

The aim of the present study was to assess the effects of alendronate (ALN) on bone remodeling following tooth extraction in a dog model.

MATERIAL AND METHODS

For the study, fifteen male Beagles dogs of approximately 12 months of age were used. Mesial roots of four mandibular premolars were endodontically treated, and the distal roots were removed. ALN concentrations of 0.5, 1, and 2 mg/mL were topically applied for 15 min, while a sterile saline was used as a negative control. After the healing period of 1, 2, and 8 weeks, the samples were analyzed by micro-CT and histology.

RESULTS

Treatment with ALN increased vertical distance between the lingual and the buccal crestal bones. While the ALN-treated sockets had preserved more lingual bone areas, control sockets showed better preservation of the buccal bone areas. ALN treatment resulted in more osteoid formation within the extraction sockets compared with the control. Higher bone volume was found in ALN groups than in the control at 2-week and 8-week healing periods, reaching the significant difference only for the extraction sockets pooled for the ALN treatment.

CONCLUSIONS

Although ALN treatment could not prevent buccal bone resorption following tooth extraction in dogs, it proved beneficial for the preservation of the lingual bone and formation of new bone within the socket. There was no clear relation between the ALN dosages and the alterations within the extraction sockets.

CLINICAL RELEVANCE

ALN affects bone remodeling of the extraction socket. The optimal concentration remains to be determined in future studies.

In vivo evaluation of chitosan based local delivery systems for atorvastatin in treatment of periodontitis

Periodontitis is a local inflammatory disease initiated by bacteria accumulation and results in cytokine mediated alveolar bone resorption and tissue destruction. In this study, the effect of locally delivered atorvastatin (2% w/v) containing chitosan formulations in the treatment of periodontitis was evaluated in rats with ligature induced periodontitis. The levels of interleukin-1beta (IL-1β), IL-6, IL-8, IL-10, transforming growth factor-β1 (TGF-β1), TGF-β2 and TGF-β3 were measured after treatment with formulations. Histomorphometric analysis included the measurements of the area of alveolar bone and the distance between cemento-enamel junction (CEJ) and connective tissue attachment to tooth. Inflammatory and osteoclastic activity scores were given semiquantitatively. Following the administration of atorvastatin, release of pro-inflammatory (IL-1β, IL-6 and IL-8) and anti-inflammatory (TGF-β1 and TGF-β2) cytokines was found to decrease, with a significant alveolar bone healing, when compared to that of control. The anti-inflammatory effect was observed to enhance in presence of chitosan. These findings suggest that chitosan based delivery system for a statin group drug, atorvastatin is a promising for the treatment of periodontal disease.

Effects of the prebiotic mannan oligosaccharide on the experimental periodontitis in rats

AIM

To evaluate the effect of the prebiotic (PREB) mannan oligosaccharide (MOS) on the progression of the experimental periodontitis (EP) and intestinal morphology in rats.

MATERIALS AND METHODS

Forty rats were randomly allocated into groups (n = 10): C (control), PREB, EP and EP-PREB. Groups PREB and EP-PREB received MOS incorporated into the feed daily. After 30 days, groups EP and EP-PREB received a cotton ligature around their mandibular first molars, kept for 14 days. Morphometrical, histomorphometrical, microcomputed tomography, gene expression analyses and immunohistochemistry were performed. Data were statistically analysed (p < 0.05).

RESULTS

Group EP-PREB showed less interproximal bone loss, area without bone in the furcation and bone porosity, and greater bone mineral density than group EP (p < 0.05). It was also observed a significant decrease in IL-10 and IFN-γ gene expression, besides a decrease in TNF-α and IL-1β and an increase in TGF-β immunolabeling score for group EP-PREB. Group EP-PREB also presented villous height and crept depth values similar to group C, while group EP presented reduced values (p < 0.05).

CONCLUSION

It can be concluded that the oral administration of MOS promotes a protective effect against alveolar bone loss caused by EP in rats, modifying histologic and immune-inflammatory parameters, in addition to protecting the intestine.

Effects of the probiotic Bifidobacterium animalis subsp. lactis on the non-surgical treatment of periodontitis. A histomorphometric, microtomographic and immunohistochemical study in rats

Lactobacillus probiotics have been investigated in periodontitis. However, the effects of the genus Bifidobacterium on periodontitis are hardly known. This study evaluated the effects of the probiotic (PROB) Bifidobacterium animalis subsp. lactis (B. lactis) HN019 as an adjunct to scaling and root planing (SRP) in rats with experimental periodontitis (EP). At baseline, 32 rats were assigned to 4 groups: C (control), PROB, EP-SRP and EP-SRP-PROB. In groups EP-SRP and EP-SRP-PROB, the mandibular first molars of the animals received a ligature. At day 14, the ligatures were removed and SRP was performed. Animals of groups PROB and EP-SRP-PROB were orally administered with 10 mL/day of 10⁹ colony forming units of B. lactis HN019 for 15 days, starting at day 14. Animals were euthanized at day 29. Histomorphometric, microtomographic and immunohistochemical analyses were performed. Microbiological effects of B. lactis on biofilm were also evaluated. Data were statistically analyzed (ANOVA, Tukey; Kruskal-Wallis, Dunn’s; Two-tailed t-test; p<0.05). Group EP-SRP-PROB presented reduced alveolar bone resorption and attachment loss when compared with Group EP-SRP (p<0.05). Group EP-SRP-PROB showed significantly fewer osteoclasts, increased expression of anti-inflammatory cytokines and reduced expression of proinflammatory cytokines compared with Group EP-SRP (p<0.05). B. lactis promoted a higher ratio between aerobic and anaerobic bacteria in biofilm samples (p<0.05). B. lactis HN019 may have a role in the treatment of EP in rats, as an adjunct to SRP.

Benefits of Bifidobacterium animalis subsp. lactis Probiotic in Experimental Periodontitis

BACKGROUND

This study evaluates effects of topical administration of probiotic bacteria of the genus Bifidobacterium on experimental periodontitis (EP) in rats.

METHODS

Thirty-two rats were divided into groups C (control; without EP), EP (EP only), C-HN019 (control+probiotic), and EP-HN019 (EP+probiotic). On day 0 of the experiment, animals of groups EP and EP-HN019 received cotton ligatures around mandibular first molars (MFMs). In groups C-HN019 and EP-HN019, 1 mL of suspensions containing Bifidobacterium animalis subsp. lactis (B. lactis) HN019 was topically administered in the subgingival region of MFMs on days 0, 3, and 7. In groups C and EP, topical administrations were performed using a sham suspension (without probiotic). All animals were euthanized at day 14. Gingival tissue, hemimandibles, and oral biofilm were collected. Data were statistically analyzed (P <0.05).

RESULTS

Group EP presented greater bone porosity, trabecular separation, and connective tissue attachment loss (CTAL) as well as reduced bone volume than all other groups (P <0.05). In group EP-HN019, there were greater proportions of Actinomyces and Streptococcus-like species and lower proportions of Veillonella parvula, Capnocytophaga sputigena, Eikenella corrodens, and Prevotella intermedia-like species than group EP. Group EP-HN019 presented greater expressions of osteoprotegerin and β-defensins than group EP (P <0.05). Group EP presented greater levels of interleukin-1β and receptor activator of nuclear factor-kappa B ligand than group EP-HN019 (P <0.05).

CONCLUSION

Topical use of B. lactis HN019 promotes a protective effect against alveolar bone loss and CTALs attributable to EP in rats, modifying immunoinflammatory and microbiologic parameters.

Favourable effects of Bacillus subtilis and Bacillus licheniformis on experimental periodontitis in rats

OBJECTIVES

The purposes of this study were to evaluate, in rats: i) the effects of Bacillus species on the development of experimental periodontitis (EP) via microtomographic, immunological and hematological assays (Experiment 1-E1); ii) the effects of Bacillus species as adjuncts to scaling and root planing (SRP) for the treatment of EP via histomorphometric and immunohistochemical analyses (Experiment 2-E2).

METHODS

In E1, 24 rats were divided into groups C1 (control), PROB1, EP1 and EP-PROB1. In groups with EP, the mandibular first molar of each animal received a ligature for 14 days. In groups PROB1, animals received Bacillus species for 44 days, starting 30 days before EP induction in Group EP-PROB1. In E2, 24 rats were assigned to groups C2 (control), PROB2, EP-SRP2 and EP-SRP-PROB2. In groups with SRP, EP was induced as described in E1. The ligatures were removed after 14 days and SRP was performed. In groups PROB2, animals received Bacillus species for 15 days, starting after SRP in Group EP-SRP-PROB2.

RESULTS

In E1, Group EP1 presented bone loss (BL) and eosinophil numbers greater than Group EP-PROB1 (P<0.05). In Group EP-PROB1, the receptor activator of nuclear factor-kB ligand (RANKL)/osteoprotegerin (OPG) ratio was similar to that of groups without EP. In E2, Group EP-SRP-PROB2 presented fewer TRAP-positive osteoclasts, lower immunolabeling pattern for a proinflammatory cytokine and decreased BL and attachment loss than Group EP-SRP2 (P<0.05).

CONCLUSIONS

Bacillus species supplementation provided a protective effect against BL and enhanced the effects of SRP in the treatment of EP in rats.

Effects of electroacupuncture on experimental periodontitis in rats

BACKGROUND

Acupuncture has shown the capability of modulating the immuno-inflammatory response of the host. This study aims to evaluate the effects of electroacupuncture (EA) on ligature-induced periodontitis in rats.

METHODS

Thirty-two animals were divided into four groups: 1) control; 2) experimental periodontitis (EP); 3) sham-treated (EP/EA-sham); and 4) treated with EA (EP/EA). For the EP groups, a ligature was placed around the right mandibular first molars at day 1. Sessions of EA or EA-sham were assigned every other day. For EA treatment, large intestine meridian points LI4 and LI11 and stomach meridian points ST36 and ST44 were used. EA-sham was performed in off-meridian points. Animals were euthanized at day 11. Histomorphometric and microtomographic analyses were performed. Immunolabeling patterns for the receptor activator of nuclear factor κB ligand (RANKL), osteoprotegerin (OPG), and tartrate-resistant acid phosphatase (TRAP) were assessed. Expressions of interleukin (IL)-1β, matrix metalloproteinase (MMP)-8, IL-6, and cyclooxygenase (COX)-2 messenger RNAs (mRNAs) were evaluated by quantitative reverse transcription-polymerase chain reaction. Data were analyzed statistically (P <0.05, analysis of variance).

RESULTS

Histomorphometric and microtomographic analyses demonstrated that group EP/EA presented reduced alveolar bone loss when compared to group EP (P <0.05). Reduced RANKL immunolabeling and fewer TRAP-positive multinucleated cells were observed in the EA-treated group in relation to group EP. No differences were observed in OPG expression among groups. EA treatment decreased the genic expression of IL-1β and MMP-8 (P <0.05), increased the mRNA expression of IL-6 (P <0.05), and did not modify the genic expression of COX-2 in animals with EP (P >0.05).

CONCLUSION

It can be concluded that EA reduced periodontal tissue breakdown and the expression of some proinflammatory mediators and a proresorptive factor in EP in rats.