Effect of methotrexate on alveolar bone loss in experimental periodontitis in Wistar rats

Desmarestia anceps Montagne modulates inflammatory response in experimental periodontitis in male Wistar rats

OBJECTIVE

Desmarestia anceps Montagne (D. anceps) seaweed has been shown to play a range of biologic activities, such as anti-inflammatory and antioxidant properties. The purpose of this study was to investigate the effects of D. anceps on pathogenesis of ligature-induced experimental periodontitis in rats.

DESIGN

Fifty-four male Wistar rats were randomly divided into six groups. Doses of D. anceps (100 and 200 mg/kg) were administered for 14 days to animals with or without ligature-induced periodontitis, in order to compare to control groups (vehicle solution). Morphometric registration of alveolar bone loss and histological analysis were conducted. Inflammatory cells were counted on hematoxylin-eosin-stained slides. Immunohistochemical expressions for interleukin-1 beta (IL-1β), tumor necrosis factor (TNF-α), receptor activator of nuclear factor kappa-Β ligand (RANKL) and bone morphogenetic protein 2 (BMP-2) were evaluated.

RESULTS

Alveolar bone loss was higher in groups exposed to ligature-induced periodontitis, but no significant differences were observed comparing different treatment and control groups. Animals that received D. anceps extracts showed significant lower counts of inflammatory cells. D. anceps promoted increased expression of BMP-2 and inhibited IL-1β, TNF-α and RANKL.

CONCLUSION

D. anceps modulates inflammatory response in experimental periodontitis in rats. Further pharmacological and immunological analyses are warranted.

Electroacupuncture Reduces Inflammation but Not Bone Loss on Periodontitis in Arthritic Rats

Periodontitis and rheumatoid arthritis (RA) are inflammatory diseases characterized by chronic inflammation and bone erosion. Electroacupuncture (EA) shows anti-inflammatory and anti-resorptive effects in experimental periodontitis (EP) and in RA. It is important to investigate whether EA shows these effects in periodontal tissues in the presence of these two inflammatory diseases or not. For this, Wistar rats were divided into six groups: control (C); experimental rheumatoid arthritis (RA; bovine type II collagen-induced (CII)); experimental periodontitis (EP); RA/EP (RA + EP); EP/EA (EP treated with EA); RA/EP/EA (RA + EP treated with EA). EP was induced 21 days after RA induction and EA was performed previously and during the EP induction period, every 3 days until the 36th experimental day. The rats were euthanized on day 39. RA was evaluated by edema and the withdrawal threshold of hind paws. The maxillae were removed, and alveolar bone loss (ABL) and bone radiographic density (BRD) were evaluated. Immunohistochemical analyses for interleukins (IL)-6 and -17 and nuclear factor (NF)-κB were performed. Our results showed that EA reduced only the pain intensity in arthritic rats. Histomorphometric, macroscopic, and radiographic analyses did not show differences between the control and EP/EA groups. EA caused a reduction in ABL and BRD only in the presence of EP. EA caused a reduction in IL-6 and -17 in all groups, but NF-κB was only reduced in the arthritic rats with EP. In conclusion, EA reduced the inflammation related to periodontitis in arthritic rats but did not prevent ABL.

Effects of Conventional Synthetic Disease-Modifying Antirheumatic Drugs on Response to Periodontal Treatment in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) and periodontitis are common chronic inflammatory diseases and periodontitis is known to be more common and more severe in patients with RA. Based on a paucity of studies about the relationship between common conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and periodontitis, this prospective study aimed to evaluate the adjunctive effect of csDMARDs on response to nonsurgical periodontal treatment in patients with RA. Thirty-two patients with RA (RA group) and 32 systemically healthy patients (control group) with periodontitis were included in this study. The RA group patients were treated with csDMARDs, such as methotrexate, hydroxychloroquine, and sulfasalazine. Conventional nonsurgical periodontal treatment with scaling and root planing was performed in both groups. The extent and severity of periodontitis were evaluated by plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) at baseline and 4 weeks after periodontal treatment. There was no statistically significant difference of periodontal parameters between the RA and control groups at baseline. Four weeks after scaling and root planing, PD reduction, and CAL gain were higher in the RA group treated with csDMARDs compared to the control group, and the difference was statistically significant (P = 0.006 and 0.003, respectively). A post hoc analysis of the RA group showed no statistically significant difference on the response to nonsurgical periodontal treatment in multiple csDMARDs therapy and addition of NSAIDs and/or steroids to csDMARDs. In patients with RA, csDMARDs showed beneficial effect on periodontal clinical parameters following the nonsurgical periodontal treatment.

Cross-Sectional Evaluation of Periodontal Status and Microbiologic and Rheumatoid Parameters in a Large Cohort of Patients With Rheumatoid Arthritis

BACKGROUND

This study evaluates periodontal conditions and microbiologic findings and their influence on rheumatologic disease parameters in patients with rheumatoid arthritis (RA).

METHODS

One hundred and sixty-eight patients with RA were included. A healthy control group (HC, n = 168) was composed according to age, sex, and smoking habits. Rheumatologic data (duration of illness, Disease Activity Score 28, rheumatic factor [RF], anti-cyclic citrullinated peptide [aCCP], medications) were extracted from patients' records. Dental examination included: 1) dental findings (decayed, missing, and/or filled adult teeth [DMF-T] index); 2) gingival inflammation (papillary bleeding index [PBI]); and 3) periodontal status (probing depth [PD], attachment loss [AL]). Periodontal condition was classified as healthy/mild, moderate, or severe periodontitis. Subgingival biofilm was analyzed regarding 11 periodontopathogenic bacteria. Statistical analyses included: 1) Kolmogorov-Smirnov test; 2) Mann-Whitney U test; 3) Pearson χ² test; 4) Kruskal-Wallis test; and 5) regression analysis; level of significance α = 5%.

RESULTS

Mean DMF-T was significantly higher in patients with RA (19.3 ± 4.8) than in HC group (16.9 ± 5.8), especially owing to number of missing teeth (RA = 6.0 ± 5.4, HC = 3.1 ± 3.3; P <0.01). Patients with RA had a significantly higher proportion of increased PD (P <0.01) and AL compared with HC group (P <0.01). Moderate to severe periodontitis was noted in 98% of patients with RA and 82% of the HC group (P <0.01). RF-positive patients with RA suffered from worse periodontal conditions than RF-negative patients (P = 0.01). Age, PBI, and presence of Treponema denticola (P <0.03) are related to periodontal condition in patients with RA. Although not statistically significant, Porphyromonas gingivalis and Fusobacterium nucleatum occur in higher concentrations more often in aCCP-positive patients with RA (P = 0.06).

CONCLUSIONS

Patients with RA had worse periodontal conditions than HC participants. Although a trend for higher F. nucleatum and P. gingivalis concentrations in aCCP-positive patients with RA was found, importance of periodontal pathogenic bacteria and rheumatoid parameters in the interrelationship between periodontitis and RA remains unclear.

Effect of avocado/soybean unsaponifiables on ligature-induced bone loss and bone repair after ligature removal in rats

BACKGROUND AND OBJECTIVE

The aim of this study was to evaluate the effects of administration of avocado/soybean unsaponifiable (ASU), a drug that is commonly used in the treatment of rheumatoid arthritis, on ligature-induced bone loss and bone repair after ligature removal in rats.

MATERIAL AND METHODS

Eighty-four rats were randomly assigned to four groups of equal size and received a daily gavage of either sterile saline [control (CTR)] or ASU (0.6 mg/kg), starting 7 d before (ASU/-7), on the day of (ASU/0) or 7 d after (ASU/+7) periodontitis induction. Periodontitis was induced by placing silk ligatures into the gingival sulcus of the second maxillary molars for 7 d; after 7 d, the ligatures were removed. Seven rats from each group were sacrificed, 7, 15 or 30 d after ligature removal. Bone resorption was evaluated by histomorphometry and micro-computed tomography (micro-CT). Immunohistochemistry was used to evaluate the expression of TRAP, RANKL and alkaline phosphatase (ALP), and quantitative PCR (qPCR) was used to evaluate the levels of interleukin-1beta (Il1β), tumor necrosis factor alpha (Tnfα), interleukin-6 (Il-6), Rankl and Alp. Statistical analysis was performed using the Shapiro-Wilk test, ANOVA and Tukey's test for normal data, and using the Kruskall-Wallis and Dunnet's tests for non-normal data (p < 0.05).

RESULTS

Histomorphometry and micro-CT analysis showed greater bone resorption in the CTR group than in the ASU/0 (15 d) and ASU/+7 (7 and 15 d) groups. The CTR group also presented with a higher expression of TRAP (15 and 30 d) and RANKL (7 and 15 d) compared with ASU/0 and ASU/+7 groups. Similarly, qPCR analysis showed higher levels of Rankl and Il1β mRNAs, and lower levels of Alp mRNA, in the CTR group compared with all other groups (for all periods).

CONCLUSION

ASU exhibited a positive effect on bone repair following ligature-induced periodontitis in rats.

Interleukin-6 receptor inhibitor tocilizumab ameliorates periodontal inflammation in patients with rheumatoid arthritis and periodontitis as well as tumor necrosis factor inhibitors

Interleukin-6 (IL-6) may play a pathological role in rheumatoid arthritis (RA) and periodontitis. Although the efficacy of medication with IL-6 receptor inhibitor, tocilizumab (TCZ), has been demonstrated in the treatment of RA, very little is known about whether TCZ therapy affects periodontitis. The aim of the present study is to compare periodontal condition in patients with RA and periodontitis before and after TCZ therapy. The study participants consisted of 20 patients with RA and periodontitis who were treated with TCZ and 40 patients with RA and periodontitis who received medication with tumor necrosis factor inhibitor (TNFI). Clinical periodontal and rheumatologic assessments and serum biochemical measurements using enzyme-linked immunosorbent assays were performed at baseline and 3 and 6 months later. TCZ and TNFI therapies significantly reduced periodontal inflammation that was determined by gingival index, bleeding on probing, and probing depth (p < 0.017), although plaque levels were comparable before and after the therapies. Both therapies also significantly decreased disease activity score including 28 joints using C-reactive protein (CRP), number of tender and swollen joints, and serum levels of anti-cyclic citrullinated peptide antibodies, rheumatoid factor, CRP, and matrix metalloproteinase-3 (p < 0.017). Additionally, a significant decrease was observed in periodontal clinical attachment level after TCZ therapy (p < 0.017), but not after TNFI therapy. TCZ therapy significantly decreased serum levels of TNF-α, total immunoglobulin G, and serum amyloid A (p < 0.017), although serum levels of IL-6 and soluble IL-6R were significantly increased (p < 0.017). These results suggest a beneficial effect of TCZ therapy on levels of periodontal inflammation in patients with RA and periodontitis, which might be related to decrease in serum inflammatory mediators.

Periodontal disease and high doses of inhaled corticosteroids alter NTPDase activity in the blood serum of rats

BACKGROUND

Certain drugs such as glucocorticoids may interfere with the modulation of periodontal disease. In contrast, corticosteroid treatment has been associated with a protective effect with regard to periodontal breakdown, depending on the dose, pathway, and exposure time. Considering the potential relevance of nucleotidases in coordinating the cardiovascular system and inflammation processes, the aim of this study was to investigate the nucleotidase activities in the blood serum of rats with periodontal disease exposed chronically to inhaled corticosteroids.

METHODS

Adult male Wistar rats (n=26) were randomly assigned to one of the following four study groups: a control group that received no intervention; a periodontal disease group that received saline solution; a 'low dose' group that received 30 μg of budesonide daily; and a corresponding 'high dose' group that received 100 μg daily over a 15-day time course. The hydrolysis of ATP, ADP, and AMP were analysed in blood serum.

RESULTS

Periodontal disease diminished the hydrolysis of ATP and enhanced the hydrolysis of ADP. Repeated administration of either a low or high dose in the periodontal disease model of inhaled corticosteroids reversed the observed increase in ADP hydrolysis, and only the repeated administration of low doses of inhaled corticosteroids was able to reverse the decrease in the hydrolysis of ATP induced by periodontal disease.

CONCLUSION

The variables investigated in this study may be involved in the pathophysiology of periodontal disease and may participate in the mechanisms that mediate the development of some of the side effects of inhaled corticosteroids.

Rheumatoid arthritis in the elderly and its relationship with periodontitis: a review

Periodontitis and rheumatoid arthritis are chronic inflammatory diseases commonly seen in the elderly. It has been proposed that the two conditions are interrelated and influence the severity of each other. Recently, the role of Porphyromonas gingivalis, a periodontopathogen, has been explained in the pathogenesis and progression of rheumatoid arthritis. It can be inferred from the present review that the two conditions share a common pathobiology, genetics and environmental risk factors. Furthermore, a thorough understanding of the aforementioned mechanisms might enable the development of conjoint treatment modalities beneficial in treating the geriatric population afflicted by both the disorders.

Effect of obesity on alveolar bone loss in experimental periodontitis in Wistar rats

Obesity has been linked to higher inflammatory status and periodontal breakdown.

Anti-inflammatory effect of the endocannabinoid anandamide in experimental periodontitis and stress in the rat

OBJECTIVE

Periodontitis is an infectious disease leading to inflammation and destruction of tissue surrounding and supporting the tooth. The progress of the inflammatory response depends on the host's immune system and risk factors such as stress. The aim of the present study was to investigate the role of the endocannabinoid anandamide (AEA) in experimental periodontitis with restraint stress, since the endocannabinoid system is known to modulate the hypothalamo-pituitary-adrenal axis as well as immune functions and has been found in human gingival tissues.

METHODS

Experimental periodontitis was induced by ligature around first inferior molars and immobilization stress for 2 h twice daily for 7 days in a rat model.

RESULTS

Corticosterone plasma levels, locomotor activity, adrenal gland weight and bone loss were increased in periodontitis and stress groups, and there was also less weight gain. The inflammatory parameters such as prostaglandin E(2) (radioimmunoassay), nitric oxide (radioconversion of (14)C-arginine), tumor necrosis factor (TNF)-α (ELISA) and interleukin (IL)-1β (Western blot) measured in the gingival tissue were significantly increased in the periodontitis groups compared to the control group. Local injection of AEA (10(-8)M, 30 µl) decreased corticosterone plasma levels and the content of the cytokines TNF-α and IL-1β in gingival tissue in periodontitis-stress groups. These AEA-induced inhibitions were mediated by CB(1) and CB(2) cannabinoid receptors since the injection of both antagonists together, AM251 (10(-6)M) and AM630 (10(-6)M) in 30 µl, prevented these effects.

CONCLUSION

The endocannabinoid AEA diminishes the inflammatory response in periodontitis even during a stressful situation.

How has neutrophil research improved our understanding of periodontal pathogenesis?

BACKGROUND

Neutrophils are the predominant cells responsible for host defence against bacterial infection. Loss of neutrophil defence, due either to deficient number or function, strongly predisposes to bacterial infections such as periodontitis. Yet, the neutrophil oxidative and proteolytic arsenal has also been implicated in perpetrating periodontal tissue damage in periodontitis.

AIM

In this review, we focus on recent developments that shed light on these two aspects of neutrophil function in periodontitis.

METHODS

Primary search: using PubMed search for "neutophil", "periodontal", and "periodontitis". Secondary search: using references from the articles found in the first stage.

RESULTS

Early histological studies showed that infiltrating neutrophils form a wall of cells abutting the junctional epithelium in periodontal inflammatory lesions. The chronic standoff between these neutrophils and the bacterial community suggests that bacterial evasion of neutrophil clearance is a major characteristic of periodontitis. Indeed, not all functional neutrophil deficiencies increase the risk of periodontitis, an observation that points the way towards identification of particular anti-bacterial pathways essential for protection against periodontal pathogens. The net result in the majority of periodontitis patients who exhibit normal neutrophil number and function, is that neutrophils accumulate in the periodontal tissue where they are available to participate in tissue destruction. Diminished neutrophil clearance further contributes to the persistence of activated neutrophils in the periodontal tissue.

CONCLUSIONS

Data on the role of neutrophils in the pathogenesis of periodontitis are mixed. Neutrophils are a critical arm of the defence against periodontitis, but bacterial evasion of the neutrophil microbicidal machinery coupled with delayed neutrophil apoptosis may transform the neutrophil from defender to perpetrator. At this stage of knowledge, attempts to induce host modulation through neutrophil suppression or activation are premature.

Effect of inhaled corticosteroid on TNF-α production and alveolar bone loss in Wistar rats

OBJECTIVE

To evaluate the effect of different concentrations of inhaled budesonide on secretion of tumoral necrosis factor-alpha (TNF-α) and on ligature-induced alveolar bone loss in Wistar rats.

MATERIALS AND METHODS

Forty-two animals were randomly divided in four groups. Control group (G1) did not receive any procedure. For the other 3 groups, alveolar bone loss was induced by placement of ligatures around the upper second molar. The contralateral molar was considered intra-group control. Group 2 (G2) was nebulized with saline solution (NaCl 0.9%). Groups 3 and 4 (G3 and G4) were nebulized with 30 μg and 100 μg budesonide, respectively. Administration of drugs was performed daily for 14 days. Blood samples were collected from all animals for analysis of TNF-α. The maxillae from G2, G3 and G4 were removed and defleshed with 9% sodium hypochlorite. Morphometric analysis of bone loss was performed in digital standard photographs. Statistical analysis was performed with one-way ANOVA, followed by Tukey HSD or Scheffé multiple comparison's test (significance level P ≤ 0.05).

RESULTS

Mean alveolar bone loss values for teeth with ligature were 0.72, 0.70 and 0.77 mm for Groups 2, 3 and 4, respectively. No statistically significant differences were found amongst groups with or without ligature. The production of TNF-α was 60% higher in the presence of ligature (G1 vs. G2/G3/G4). No effect was observed in TNF-α secretion after inhalation of budesonide.

CONCLUSION

Inhaled budesonide in different concentrations did not alter alveolar bone loss and TNF-α secretion in male Wistar rats.

Evaluation of two morphometric methods of bone loss percentages caused by periodontitis in rats in different locations

Objective

The present study evaluated morphometrically bone loss percentages in experimental periodontitis in rats, comparing different locations (lingual mandible, palatal maxilla and buccal maxilla) and two evaluation methods (distance and area methods).

Material and Methods

Ligatures were placed around the maxillary right second molar and around the mandibular right first molar in 14 female Wistar rats. The contralateral molars served as intragroup controls. After 4 weeks, the rats were sacrificed and their mandible and maxilla were removed. The specimens were dissected and stained with methylene blue dye. Bone loss was evaluated by two different methods on the surfaces of the defleshed jaw. In the first method, the distance from the cementoenamel junction (CEJ) to the alveolar bone crest was measured in the roots of teeth associated with ligature. In the second method, the area of bone loss was determined using the alveolar tissue bone, CEJ and the proximal region of roots associated with the ligature as reference. The data were converted to bone loss percentages caused by ligature: (ligated – unligated) x 100/ligated.

Results

When comparing the distance and area methods, no statistically significant difference was observed (p>0.05). Both methodologies indicated that the maxilla presented greater bone loss than the mandible and it was more accentuated on the buccal side than on the palatal side (p<0.05).

Conclusion

The findings of this study show that both the area and the distance methods can be used to evaluate bone loss caused by ligature placement in rats, and suggest applying the morphometric methodology to the maxilla on the buccal side.

Effect of neonatal clomipramine in the pathogenesis of ligature-induced periodontitis in Lewis rats

OBJECTIVE

The aim of this study was to verify the association between an endogenous depression model and the development of ligature-induced periodontitis in rats.

MATERIAL AND METHODS

Nine male Lewis rats received 30 mg/kg clomipramine from neonatal day 8 to day 21 (depressed group), while 13 control Lewis rats were left untouched (control group). On day 150, ligatures were placed around the 2nd upper molars in both groups, i.e. the contralateral molar of the intra-group control. On day 190, the rats were killed and the maxillae were defleshed. The distance between the cemento-enamel junction and the alveolar bone crest was measured by a blinded examiner using standardized digital photographs.

RESULTS

The depressed rats showed hyperactivity in open field on day 142 and greater attempts to escape on day 143 compared to controls. The other behavioral data did not show statistically significant differences between the groups (Mann-Whitney, p>0.05). In teeth with ligature, mean alveolar bone loss varied from 0.51 to 0.60 and from 0.63 to 0.64 mm for tests and controls, respectively (t-test, p>0.05). In teeth without ligature, these values varied from 0.38 to 0.43 and 0.42 to 0.45 mm in the test and control groups, respectively (t-test, p>0.05).

CONCLUSION

Induced depression did not alter ligature-induced bone loss in Lewis rats.

Effect of body weight in the pathogenesis of ligature-induced periodontal disease in Wistar rats

OBJECTIVE

The aim of this study was to compare ligature-induced alveolar bone loss between obese and non-obese rats.

MATERIAL AND METHODS

Thirty female Wistar rats were randomly divided into two groups: a test group comprising 14 rats fed with a "cafeteria diet" for 120 days in order to gain weight and a control group comprising 16 regularly fed rats. Ligatures were placed around the 2nd upper molars, and the contralateral teeth served as intra-group controls. After 30 days, the animals were killed and the maxillae were removed. Sodium hypochlorite was used to prepare the specimens, and the cementum-enamel junction was stained with methylene blue 1%. Morphometric analysis of alveolar bone loss was by standardized digital photographs and the distance between the cementum-enamel junction and the alveolar bone crest was measured using the software Image Tool 3.0.

RESULTS

Body weight differed statistically between test and controls (268.6 and 242.4 g, respectively). Test animals demonstrated a mean (SD) alveolar bone loss of 0.51 (0.11) mm and in the controls 0.52 (0.14) mm in teeth with ligatures. No statistically significant differences were observed (ANOVA+Tukey), except for teeth with and without ligatures in both groups.

CONCLUSIONS

The establishment and progression of alveolar bone loss in rats was not influenced by body weight in the present study.