Runx2介导TGF-β1调控成釉细胞MMP20基因表达的研究

目的:研究Runx2在TGF-β1调控小鼠成釉细胞金属基质蛋白酶-20(matrix metalloprotei-nase 20,MMP20)基因表达中的作用。方法:首先利用双荧光素酶基因报告系统分析TGF-β1对MMP20基因启动子转录活性的影响;然后利用染色体免疫共沉淀(Chromatin Immunoprecipitation,ChIP)方法观察Runx2与MMP20特异性结合位点之间的相互作用,并利用基因定点突变和双荧光素酶基因报告系统分析Runx2对MMP20基因启动子转录活性的影响;最后运用小RNA干扰技术使Runx2基因沉默,实时定量RT-PCR技术观察TGF-β1诱导MMP20基因表达的改变。结果:TGF-β1刺激成釉细胞后,MMP20启动子在-87～+23区域转录活性无明显变化外,其他各区域转录活性均增强。利用ChIP研究发现Runx2与MMP20基因核心启动子的特征性序列"TGTGGG"相互作用;将该特征性序列由"TGTGGG"突变为"TGTAAG"后,利用双荧光素酶基因报告系统发现Runx2对MMP20基因启动子转录活性的影响减弱;利用小RNA干扰技术使Runx2基因沉默后,TGF-β1上调MMP20基因表达的作用减弱。结论:TGF-β1通过转录因子Runx2调控成釉细胞MMP20的表达。     

Enamel matrix derivative induces production of vascular endothelial cell growth factor in human gingival fibroblasts

Enamel matrix derivative (EMD) may enhance periodontal wound healing by inducing angiogenesis. We sought to investigate the effect and the mechanism of action of EMD on vascular endothelial growth factor (VEGF) production by human gingival fibroblasts. Cells were stimulated with EMD, transforming growth factor‐β1 (TGF‐β1), or fibroblast growth factor 2 (FGF‐2), with or without antibodies to TGF‐β1 or FGF‐2. The levels of VEGF in the culture media were measured using an ELISA. We examined the effects of SB203580 [a p38 mitogen‐activated protein kinase (MAPK) inhibitor], U0126 [an extracellular signal‐regulated kinase (ERK) inhibitor], SP600125 [a c‐Jun N‐terminal kinase (JNK) inhibitor], and LY294002 [a phosphatidylinositol 3‐kinase (PI3K)/Akt inhibitor] on EMD‐induced VEGF production. Enamel matrix derivative stimulated the production of VEGF in a dose‐ and time‐dependent manner. Treatment of human gingival fibroblasts with antibodies to TGF‐β1 or FGF‐2 significantly decreased EMD‐induced VEGF production, whereas the addition of exogenous TGF‐β1 and FGF‐2 stimulated VEGF production. Enamel matrix derivative‐induced VEGF production was significantly attenuated by SB203580, U0126, and LY294002. Our results suggest that EMD stimulates VEGF production partially via TGF‐β1 and FGF‐2 in human gingival fibroblasts and that EMD‐induced VEGF production is regulated by ERK, p38 MAPK, and PI3K/Akt pathways. Enamel matrix derivative‐induced production of VEGF by human gingival fibroblasts may be involved in the enhancement of periodontal wound healing by inducing angiogenesis.     

Collagen Membranes Adsorb the Transforming Growth Factor‐β Receptor I Kinase‐Dependent Activity of Enamel Matrix Derivative

Background: Enamel matrix derivative (EMD) and collagen membranes (CMs) are simultaneously applied in regenerative periodontal surgery. The aim of this study is to evaluate the ability of two CMs and a collagen matrix to adsorb the activity intrinsic to EMD that provokes transforming growth factor (TGF)‐β signaling in oral fibroblasts. Methods: Three commercially available collagen products were exposed to EMD or recombinant TGF‐β1, followed by vigorous washing. Oral fibroblasts were either seeded directly onto collagen products or were incubated with the respective supernatant. Expression of TGF‐β target genes interleukin (IL)‐11 and proteoglycan 4 (PRG4) was evaluated by real time polymerase chain reaction. Proteomic analysis was used to study the fraction of EMD proteins binding to collagen. Results: EMD or TGF‐β1 provoked a significant increase of IL‐11 and PRG4 expression of oral fibroblasts when seeded onto collagen products and when incubated with the respective supernatant. Gene expression was blocked by the TGF‐β receptor I kinase inhibitor SB431542. Amelogenin bound most abundantly to gelatin‐coated culture dishes. However, incubation of palatal fibroblasts with recombinant amelogenin did not alter expression of IL‐11 and PRG4. Conclusion: These in vitro findings suggest that collagen products adsorb a TGF‐β receptor I kinase‐dependent activity of EMD and make it available for potential target cells.     

Effect of cytokine and antigen stimulation on peripheral blood lymphocyte syndecan‐1 expression

Introduction: Cytokines are not only produced by activated lymphocytes but also interact with a number of cell‐surface molecules on the same cells. Syndecan‐1 is one such cell‐surface molecule, which has the capacity to bind a variety of growth factors as well as cytokines. The aim of this study was to examine the effects of transforming growth factor β (TGF‐β), interleukin‐1 (IL‐1), IL‐2, IL‐4, lipopolysaccharide (LPS) from Porphyromonas gingivalis and tetanus toxoid on syndecan‐1 expression by B and T lymphocytes. Methods: B and T lymphocytes were obtained from the peripheral blood of healthy donors. Following exposure to the above growth factors, cytokines and antigens, syndecan‐1 expression was determined by flow cytometry. Results: Subjects could be categorized as high or low expressors of syndecan‐1. In the high‐responder group TGF‐β1 alone resulted in a significant increase in syndecan‐1 expression by both B and T cells. None of the other cytokines and antigens produced a significant response. When analysed in combination, TGF‐β1 in combination with IL‐2, IL‐4, P. gingivalis LPS and tetanus toxoid all produced significant increases in syndecan‐1 expression by B cells. For T cells, combinations of TGF‐β1 with IL‐2 and tetanus toxoid resulted in increased syndecan‐1 expression. Conclusions: Both B and T lymphocytes synthesize the cell‐surface proteoglycan syndecan‐1 and its expression can be modulated by TGF‐β1, either alone or in combination with IL‐2, IL‐4 and LPS from P. gingivalis and tetanus toxoid. While these may reflect general responses under inflammatory conditions their biological significance requires further investigation.     

Sequential process in brain‐derived neurotrophic factor‐induced functional periodontal tissue regeneration

We recently demonstrated that brain‐derived neurotrophic factor (BDNF) promotes periodontal tissue regeneration. The purpose of this study was to establish an essential component of a rational approach for the clinical application of BDNF in periodontal regenerative therapy. Here, we assessed the sequence of early events in BDNF‐induced periodontal tissue regeneration, especially from the aspect of cementum regeneration. Brain‐derived neurotrophic factor was applied into experimental periodontal defects in Beagle dogs. The localization of cells positive for neurotrophic tyrosine kinase, receptor, type 2, proliferating cell nuclear antigen, osteopontin, integrin αVβ3, and integrin α2β1 was evaluated by immunohistochemistry. The effects of BDNF on adhesion of cultured human periodontal ligament cells was examined by an in vitro study. The results suggest that BDNF could induce rapid cementum regeneration by stimulating adhesion, proliferation, and differentiation of periodontal ligament cells in the early regenerative phase, resulting in enhancement of periodontal tissue regeneration.     

Transforming growth factor-beta1 gene expression and cyclosporine A-induced gingival overgrowth: a pilot study

Aims: The relationship between gingival overgrowth (GO) induced by cyclosporine A (CsA) and transforming growth factor‐β1 (TGF‐β1) remains unclear. The aims of the present study were to evaluate TGF‐β1 gene expression under different immunosuppressive treatments and its association with TGF‐β1 gene functional polymorphism and GO in renal transplant recipients. Material and Methods: The study included 98 CsA‐treated renal transplant recipients (with and without GO) and 44 tacrolimus‐treated transplant patients (without GO). TGF‐β1 mRNA expression was measured using a real‐time quantitative polymerase chain reaction assay. The levels were correlated with TGF‐β1 gene polymorphisms at codons 10 and 25, with different immunosuppressive treatment and GO. Results: The level of TGF‐β1 gene expression was insignificantly lower in the CsA‐treated group compared with the tacrolimus group, and significantly lower in the group with GO compared with patients without GO. In tacrolimus‐ and CsA‐treated patients, but not in patients with GO, the level of TGF‐β1 gene expression was associated with functional phenotypes of TGF‐β1. The incidence, degree and extent of GO were higher in recipients with lower TGF‐β1 gene expression. Conclusions: Lower level TGF‐β1 gene expression, not functional polymorphism, in patients treated with CsA may be considered to be a risk factor for GO.     

EGF/TGFβ1 co‐stimulation of oral squamous cell carcinoma cells causes an epithelial–mesenchymal transition cell phenotype expressing laminin 332

J Oral Pathol Med (2011) 40 : 46–54 Epithelial–mesenchymal transition (EMT) is suggested to be crucial for the development of an invasive and metastatic carcinoma cell phenotype. Therefore, the definition of this phenotype is of great clinical interest. We recently evidenced vimentin positive cells in oral squamous cell carcinoma (OSCC) invasive front expressing laminin γ2 chain mRNA implicating an EMT origin of these cells. To further elucidate the nature of these cells, we have investigated the relation between EMT criteria and laminin‐332 expression in a cell culture model of transforming growth factor beta‐1 (TGFβ1)/epithelial growth factor (EGF) long time co‐stimulation. We demonstrate that in contrast to TGFβ1 or EGF alone, co‐stimulation induces phenotype transition in OSCC cells which fulfils the criteria of EMT in terms of vimentin up‐regulation and E‐cadherin down‐regulation on protein level as well as cell scattering. Furthermore, cells displayed a strongly enhanced invasiveness and adhesion to type I‐IV collagens. Phenotype transition is accompanied by an enhanced expression of laminin‐332, especially of its γ2 chain. We further analyse the expression of extracellular matrix related genes by RT‐PCR profiling. With respect to strongly enhanced proteins, data confirm the EMT phenotype of co‐stimulated OSCC cells and expression of laminin‐332. Furthermore, alpha catenin, collagen type 16, the integrin α7 and β1 chains, and MMP11 are suggested as candidates with potential role in EMT in OSCC. In summary we are able to show that EMT in OSCC is mediated by multiple growth factors and is accompanied by laminin γ2 chain up‐regulation evidencing the existence of an intermediate Vim⁺/Ln332⁺ EMT phenotype as seen in situ.     

Effects of tobacco smoke on the secretion of interleukin‐1β, tumor necrosis factor‐α, and transforming growth factor‐β from peripheral blood mononuclear cells

Alterations of the host response caused by short‐term exposure to high levels of smoke during the act of smoking (acute smoke exposure) as well as long‐term exposure to lower levels of tobacco substances in the bloodstream of smokers (chronic smoke exposure) may play a role in the pathogenesis of periodontal diseases in smokers. In this study, we examined the secretion of three cytokines [interleukin (IL)‐1β, tumor necrosis factor (TNF)‐α, and transforming growth factor (TGF)‐β] from mononuclear blood cells from current smokers and non‐smokers exposed to in vitro tobacco smoke (which may be comparable to in vivo acute smoke exposure) and mononuclear blood cells from current smokers not exposed to further in vitro smoke (which may be comparable to chronic smoke exposure). Peripheral blood mononuclear cells were isolated from eight healthy current smokers and eight healthy non‐smokers, plated in culture wells, exposed in vitro for 1–5 min to cigarette smoke in a smoke box system or not exposed (baseline controls), and then incubated without further smoke exposure for another 24 h. Supernatants from each well were then collected and assayed for the concentrations of the three cytokines by enzyme‐linked immunosorbent assay (ELISA). At baseline, mean IL‐1β levels were higher in smokers than in non‐smokers (mean: 10.6 vs. 5.9 pg/ml, anova : P < 0.05). In both smokers and non‐smokers, secreted levels of IL‐1β increased from 0 to 5 min of in vitro smoke exposure (mean: 5.9–9.9 pg/ml, t‐test: P < 0.05 for non‐smokers only) with levels in smokers higher than in non‐smokers (P > 0.05). Mean TNF‐α levels increased from 0 to 2 min of smoke exposure and decreased from 2 to 5 min in smokers and non‐smokers, with higher levels in non‐smokers than smokers at all time‐points (P > 0.05). Mean TGF‐β levels were higher in smokers than in non‐smokers at all time‐points (mean: 180.5 vs. 132.0 pg/ml, P < 0.05 at 5 min only) with no significant alteration of the pattern of secretion with cigarette smoke exposure. These observed alterations in the secretion of cytokines from mononuclear blood cells in smokers, relative to non‐smokers, and with in vitro smoke exposure may play a role in the pathogenesis of periodontal diseases in smokers.     

Insulin‐like growth factor‐binding protein‐2 and ‐3 in gingival crevicular fluid

Takenouchi Y, Ohshima M, Yamaguchi Y, Nishida T, Senda N, Idesawa M, Otsuka K, Ito K. Insulin‐like growth factor‐binding protein‐2 and ‐3 in gingival crevicular fluid. J Periodont Res 2010; 45: 803–808. © 2010 John Wiley & Sons A/S Background and Objective: Insulin‐like growth factor‐binding proteins (IGFBPs) are crucial regulators of insulin‐like growth factor (IGF). They enhance or inhibit IGF functions, but also exhibit IGF‐independent effects. In a previous study, we detected, qualitatively, IGFBP‐2 and ‐3 in gingival crevicular fluid using a cytokine antibody array. Here we extended these results using an ELISA to determine the concentrations of IGFBP‐2 and ‐3 in gingival crevicular fluid. In addition, we explored whether the expression of IGFBP‐2 and IGFBP‐3 correlates with periodontal disease severity. Material and Methods: Gingival crevicular fluid samples from 92 sites of 12 patients affected with periodontal disease and from 100 sites of 19 healthy volunteers, were collected, divided into two groups and analyzed by ELISA for IGFBP‐2 and ‐3 expression. The potential correlation among probing depth, gingival index and the concentrations of IGFBP‐2 and ‐3 was analyzed. Results: Positive correlations were observed between the concentration of IGFBP‐2 and probing depth and gingival index, but not for IGFBP‐3. The IGFBP‐2 concentrations at bleeding on probing‐positive sites and at sites with a probing depth of ≥ 4 mm were higher than at bleeding on probing‐negative sites and at sites with a probing depth of ≤ 3 mm. Conclusion: These results indicate that IGFBP‐2 is a potential novel marker for periodontal disease progression. As IGFBP‐2 modulates bone metabolism and cell migration, IGFBP‐2 in the gingival crevicular fluid may reflect periodontal disease activity.     

The expressions of IGF‐1, BMP‐2 and TGF‐β1 in cartilage of condylar hyperplasia

Summary Condylar hyperplasia is a complex post‐natal growth abnormality of the mandible and condyle, which leads to facial asymmetry. We investigated the distributions of insulin‐like growth factors (IGF‐1), bone morphogenetic protein‐2 (BMP‐2) and transforming growth factor‐β1 (TGF‐β1) in cartilage of condylar hyperplasia and revealed relationships between age and the cartilaginous thickness. Twenty patients with condylar hyperplasia were divided into four histopathological types. The cartilaginous thickness and age in different histological types were analysed, and the localizations of IGF‐1, BMP‐2 and TGF‐β1 were detected by immunohistochemistry analysis. The cartilaginous thickness of condylar hyperplasia significantly increased. The cartilaginous thickness of type III was significantly thicker than type I and type II, Bivariate correlation revealed a significant correlations between age and the cartilaginous thickness (r = 0·68, P = 0·01). However, the expressions of IGF‐1, BMP‐2 and TGF‐β1 were the strongest in type I. In almost all types of condylar hyperplasia, the presence of IGF‐1 and BMP‐2 was found mainly in the proliferative chondrocyte layer and the hypertrophic chondrocyte layer, and only a few in the calcified chondrocyte layer. The presence of TGF‐β1 widely distributed from the fibrous articular surface to the calcified cartilage. These findings suggest that the proliferative activity of cartilage in condylar hyperplasia is strongly associated with age and cartilaginous thickness. Therefore, the four pathological types of condylar hyperplasia seem more likely to be four discontinuous stages.     

Folic acid rescue of ATRA‐induced cleft palate by restoring the TGF‐β signal and inhibiting apoptosis

J Oral Pathol Med (2010) 40 : 433–439 Background: Cleft palate is a frequent congenital malformation with a heterogeneous etiology, for which folic acid (FA) supplementation has a protective effect. To gain more insight into the molecular pathways affected by FA, TGF‐β signaling and apoptosis in mouse embryonic palatal mesenchymal (MEPM) cells of all‐trans retinoic acid (ATRA)‐induced cleft palate in organ culture were tested. Methods: C57BL/6J mice embryonic palates were explanted on embryonic day 14 and cultured in DMEM/F12 medium with or without ATRA or FA for 72 h. The palatal fusion was examined by light microscopy. Immunohistochemistry was used to detect TGFβ3/TGF receptor II and caspase 9 in MEPM cells. TUNEL was used to detect apoptosis. Results: Similar to development in vivo, palatal development and fusion were normal in control medium. ATRA inhibited palatal development and induced cleft palate, which can be rescued by FA. A higher apoptosis rate and caspase‐9 in MEPM cells were detected in the ATRA group than in the control or the ATRA + FA group. Compared with the control or the ATRA + FA group, ATRA had little effect on TGF‐β3 in MEPM cells but significantly inhibited TGF‐β receptor II. Conclusions: Folic acid can rescue the cultured palates to continue developing and fusing that were inhibited and resulted in cleft palate by ATRA. Apoptosis and TGFβ signaling in MEPM cells were involved in folic acid rescued ATRA‐induced cleft palate.     

Hypoxia inducible factor‐1α expression in areca quid chewing‐associated oral squamous cell carcinomas

Oral Diseases (2010) 16 , 696–701 Objectives: Hypoxia inducible factor (HIF)‐1α gene expression is mainly induced by tissue hypoxia. Overexpression of HIF‐1α has been demonstrated in a variety of cancers. The aim of this study was to compare HIF‐1α expression in normal human oral epithelium and areca quid chewing‐associated oral squamous cell carcinoma (OSCC) and further to explore the potential mechanisms that may lead to induce HIF‐1α expression. Methods: Twenty‐five OSCC from areca quid chewing‐associated OSCC and 10 normal oral tissue biopsy samples without areca quid chewing were analyzed by immunohistochemistry. The oral epithelial cell line GNM cells were challenged with arecoline, a major areca nut alkaloid, by using Western blot analysis. Furthermore, glutathione precursor N‐acetyl‐l ‐cysteine (NAC), AP‐1 inhibitor curcumin, extracellular signal‐regulated protein kinase inhibitor PD98059, and protein kinase C inhibitor staurosporine were added to find the possible regulatory mechanisms. Results: Hypoxia inducible factor‐1α expression was significantly higher in OSCC specimens than normal specimen (P < 0.05). Arecoline was found to elevate HIF‐1α expression in a dose‐ and time‐dependent manner (P < 0.05). The addition of NAC, curcumin, PD98059, and staurosporine markedly inhibited the arecoline‐induced HIF‐1α expression (P < 0.05). Conclusions: Hypoxia inducible factor‐1α expression is significantly upregulated in areca quid chewing‐associated OSCC and HIF‐1α expression induced by arecoline is downregulated by NAC, curcumin, PD98059, and staurosporine.     

Transforming growth factor‐β‐regulated fractalkine as a marker of erosive bone invasion in oral squamous cell carcinoma

Patients with oral squamous cell carcinoma (OSCC) bone invasion are surgically treated with bone resection, which results in severe physical and psychological damage. Here, we investigated the potential of fractalkine (CX3CL1), which is regulated by transforming growth factor (TGF‐β), as a novel biomarker for correct prediction and early detection of OSCC‐associated bone invasion. TGF‐β knockdown and treatment with a TGF‐β‐neutralizing antibody decreased the level of fractalkine in the culture media of HSC‐2 and YD10B OSCC cells. Treatment with a fractalkine‐neutralizing antibody reduced TGF‐β‐stimulated invasion by HSC‐2 and YD10B cells. Fractalkine treatment increased the viability, invasion, and uPA secretion of both OSCC cell lines. Furthermore, OSCC cell bone invasion was assessed following subcutaneous inoculation of wild‐type or TGF‐β knockdown OSCC cells in mouse calvaria. TGF‐β knockdown prevented erosive bone invasion, reduced the number of osteoclasts at the tumor‐bone interface, and downregulated fractalkine expression in mouse tumor tissues. Our results indicate that the production of fractalkine is stimulated by TGF‐β and mediates TGF‐β‐induced cell invasion in several OSCC cell lines showing an erosive pattern of bone invasion. Fractalkine may be a useful predictive marker and therapeutic target for OSCC‐induced bone destruction.     

18β‐Glycyrrhetinic acid inhibits periodontitis via glucocorticoid‐independent nuclear factor‐κB inactivation in interleukin‐10‐deficient mice

Sasaki H, Suzuki N, AlShwaimi E, Xu Y, Battaglino R, Morse L, Stashenko P. 18β‐Glycyrrhetinic acid inhibits periodontitis via glucocorticoid‐independent nuclear factor‐κB inactivation in interleukin‐10‐deficient mice. J Periodont Res 2010; 45: 757–763. © 2010 John Wiley & Sons A/S Background and Objective: 18β‐Glycyrrhetinic acid (GA) is a natural anti‐inflammatory compound derived from licorice root extract (Glycyrrhiza glabra). The effect of GA on experimental periodontitis and its mechanism of action were determined in the present study. Material and Methods: Periodontitis was induced by oral infection with Porphyromonas gingivalis W83 in interleukin‐10‐deficient mice. The effect of GA, which was delivered by subcutaneous injections in either prophylactic or therapeutic regimens, on alveolar bone loss and gingival gene expressions was determined on day 42 after initial infection. The effect of GA on lipopolysaccharide (LPS)‐stimulated macrophages, T cell proliferation and osteoclastogenesis was also examined in vitro. Results: 18β‐Glycyrrhetinic acid administered either prophylactically or therapeutically resulted in a dramatic reduction of infection‐induced bone loss in interleukin‐10‐deficient mice, which are highly disease susceptible. Although GA has been reported to exert its anti‐inflammatory activity via downregulation of 11β‐hydroxysteroid dehydrogenase‐2 (HSD2), which converts active glucocorticoids to their inactive forms, GA did not reduce HSD2 gene expression in gingival tissue. Rather, in glucocorticoid‐free conditions, GA potently inhibited LPS‐stimulated proinflammatory cytokine production and RANKL‐stimulated osteoclastogenesis, both of which are dependent on nuclear factor‐κB. Furthermore, GA suppressed LPS‐ and RANKL‐stimulated phosphorylation of nuclear factor‐κB p105 in vitro. Conclusion: These findings indicate that GA inhibits periodontitis by inactivation of nuclear factor‐κB in an interleukin‐10‐ and glucocorticoid‐independent fashion.     

Exenatide and Sitagliptin Decrease Interleukin 1β, Matrix Metalloproteinase 9, and Nitric Oxide Synthase 2 Gene Expression But Does Not Reduce Alveolar Bone Loss in Rats With Periodontitis

Background: New drugs for the treatment of diabetes, glucagon‐like peptide‐1 (GLP‐1) receptor agonists and inhibitors of dipeptidyl peptidase‐4 (DPP‐4) have shown pleiotropic effects on bone metabolism and anti‐inflammatory properties. The aim of this study is to evaluate the effects of exenatide (GLP‐1 agonist) and sitagliptin (DPP‐4 inhibitor) during periodontitis induction by ligature insertion in rats. Methods: Forty rats were divided into four groups: 1) animals with induced periodontitis that received exenatide (EG); 2) animals with induced periodontitis that received sitagliptin (SG); 3) animals with induced periodontitis and without drug treatment (LG); and 4) animals without induced periodontitis and without drug treatment (controls). The drugs were administered for 28 days. On the day the animals were sacrificed, blood was collected for analysis of glucose and DPP‐4 levels. The gene expressions of prostaglandin‐endoperoxide synthase 2, tissue inhibitor of metalloproteinase 1, Dpp4, nitric oxide synthase 2 (Nos2), interleukin 1β (Il1b), and matrix metalloproteinase 9 (Mmp9) in the gingiva; support and alveolar bone loss; connective tissue attachment; and the quantity of gingival collagen were evaluated. Results: Exenatide and sitagliptin treatments have led to a lower percentage of weight gain but did not influence glycemia. Sitagliptin reduced the serum concentration of DPP‐4. Interestingly, although the gene expression profile has revealed a downregulation of Mmp9, Nos2, and Il1b in both EG and SG compared to LG, a significant protective effect was not observed on alveolar bone and collagen tissue in this model. Conclusion: Regardless of the reduction of the expression of Il1b, Nos2, and Mmp9, the drugs were not effective in the stabilization or reduction of alveolar bone loss and collagen degradation in rats.