PI3K/Akt mediates expression of TNF‐α mRNA and activation of NF‐κB in calyculin A‐treated primary osteoblasts

Objective: The effect of calyculin A (CA), a serine/threonine protein phosphatase inhibitor, on tumor necrosis factor‐α (TNF‐α) in primary osteoblasts was investigated to determine whether protein phosphatases could affect primary osteoblasts and if so which signaling pathways would be involved. Materials and methods: Primary osteoblasts were prepared from newborn rat calvaria. Cells were treated with 1 nM CA for different time periods. The expressions of TNF‐α and GAPDH mRNA were determined by RT‐PCR. Cell extracts were subjected to SDS‐PAGE and the activation of Akt and NF‐κB were analyzed by western blotting. Results: Calyculin A‐treatment markedly increased the expression of TNF‐α mRNA and enhanced the phosphorylation level of Akt (Ser473) in these cells. Pretreatment with the PI3K inhibitor LY294002 suppressed the increase in TNF‐α mRNA expression and the phosphorylation of Akt in response to CA. Western blot analysis showed that CA stimulated the phosphorylation and nuclear translocation of NF‐κB in primary osteoblasts, and these responses were blocked by pretreatment with LY294002. Conclusion: Calyculin A elicits activation of PI3K/Akt pathway which leads to expression of TNF‐α mRNA and activation of NF‐κB. This NF‐κB activation involves both phosphorylation and nuclear translocation of NF‐κB.     

Carbon monoxide releasing molecule‐3 inhibits concurrent tumor necrosis factor‐α‐ and interleukin‐1β‐induced expression of adhesion molecules on human gingival fibroblasts

Song H, Zhao H, Qu Y, Sun Q, Zhang F, Du Z, Liang W, Qi Y, Yang P. Carbon monoxide releasing molecule‐3 inhibits concurrent tumor necrosis factor‐α‐ and interleukin‐1β‐induced expression of adhesion molecules on human gingival fibroblasts. J Periodont Res 2011; 46: 48–57. © 2010 John Wiley & Sons A/S Background and Objective: Carbon monoxide releasing molecule‐3 (CORM‐3) is a newly reported compound that has shown anti‐inflammatory effects in a number of cells. In this study, we aimed to investigate the influence of CORM‐3 on concurrent tumor necrosis factor‐α (TNF‐α)‐ and interleukin (IL)‐1β‐induced expression of adhesion molecules on human gingival fibroblasts (HGF). Material and Methods: HGF were cultured from the explants of normal gingival tissues. Cells were costimulated with TNF‐α and IL‐1β in the presence or absence of CORM‐3 for different periods of time. The expression of adhesion molecules, nuclear factor‐kappaB (NF‐κB) and phosphorylated p38 was studied using western blotting. RT‐PCR was applied to check the expression of the adhesion molecules at the mRNA level. The activity of NF‐κB was analysed using a reporter gene assay. Results: CORM‐3 inhibited the up‐regulation of intercellular adhesion molecule 1, vascular cell adhesion molecule 1 and endothelial leukocyte adhesion molecule in HGF after costimulation with TNF‐α and IL‐1β, which resulted in the decreased adhesion of peripheral blood mononuclear cells to these cells. Sustained activation of the NF‐κB pathway by costimulation with TNF‐α and IL‐1β was suppressed by CORM‐3, which was reflected by a reduced NF‐κB response element‐dependent luciferase activity and decreased nuclear NF‐κB‐p65 expression. CORM‐3 inhibited MAPK p38 phosphorylation in response to stimulation with proinflammatory cytokines. Conclusion: The results of this study bode well for the application of CORM‐3 as an anti‐inflammatory agent to inhibit NF‐κB activity and to suppress the expression of adhesion molecules on HGF, which suggests a promising potential for CORM‐3 in the treatment of inflammatory periodontal disease.     

Down‐regulation of interleukin‐1α‐induced matrix metalloproteinase‐13 expression via EP1 receptors by prostaglandin E2 in human periodontal ligament cells

In the present study, we investigated the effect of prostaglandin (PG) E₂ on matrix metalloproteinase (MMP)‐13 production in human periodontal ligament cells stimulated with interleukin (IL)‐1α. IL‐1α enhanced both MMP‐13 and PGE₂ production. Indomethacin, a nonselective cyclooxygenase inhibitor, and NS‐398, a specific cyclooxygenase‐2 (COX‐2) inhibitor, significantly enhanced IL‐1α‐induced MMP‐13 production in periodontal ligament cells, although both the agents completely inhibited IL‐1α‐induced PGE₂ production. Exogenous PGE₂ reduced IL‐1α‐induced MMP‐13 mRNA and protein production in a dose‐dependent manner. 17‐phenyl‐ω‐trinor PGE₂, a selective EP₁ receptor agonist, mimicked the inhibitory effect of PGE₂ on IL‐1α‐induced MMP‐13 mRNA and protein production. On the basis of these data, we suggest that COX‐2‐dependent PGE₂ down‐regulates IL‐1α‐elicited MMP‐13 production via EP₁ receptors in human periodontal ligament cells. PGE₂ may be involved in the regulation of destruction of extracellular matrix components in periodontal lesions.     

Aloin Inhibits Interleukin (IL)‐1β−Stimulated IL‐8 Production in KB Cells

Background: Interleukin (IL)‐1β, which is elevated in oral diseases including gingivitis, stimulates epithelial cells to produce IL‐8 and perpetuate inflammatory responses. This study investigates stimulatory effects of salivary IL‐1β in IL‐8 production and determines if aloin inhibits IL‐1β?stimulated IL‐8 production in epithelial cells. Methods: Saliva was collected from volunteers to determine IL‐1β and IL‐8 levels. Samples from volunteers were divided into two groups: those with low and those with high IL‐1β levels. KB cells were stimulated with IL‐1β or saliva with or without IL‐1 receptor agonist or specific mitogen‐activated protein kinase (MAPK) inhibitors. IL‐8 production was measured by enzyme‐linked immunosorbent assay (ELISA). MAPK protein expression involved in IL‐1β?induced IL‐8 secretion was detected by Western blot. KB cells were pretreated with aloin, and its effect on IL‐1β?induced IL‐8 production was examined by ELISA and Western blot analysis. Results: Saliva with high IL‐1β strongly stimulated IL‐8 production in KB cells, and IL‐1 receptor agonist significantly inhibited IL‐8 production. Low IL‐1β–containing saliva did not increase IL‐8 production. IL‐1β treatment of KB cells induced activation of MAPK signaling molecules as well as nuclear factor‐kappa B. IL‐1β?induced IL‐8 production was decreased by p38 and extracellular signal‐regulated kinase (ERK) inhibitor treatment. Aloin pretreatment inhibited IL‐1β?induced IL‐8 production in a dose‐dependent manner and inhibited activation of the p38 and ERK signaling pathway. Finally, aloin pretreatment also inhibited saliva‐induced IL‐8 production. Conclusions: Results indicated that IL‐1β in saliva stimulates epithelial cells to produce IL‐8 and that aloin effectively inhibits salivary IL‐1β–induced IL‐8 production by mitigating the p38 and ERK pathway. Therefore, aloin may be a good candidate for modulating oral inflammatory diseases.     

Experience with anti‐TNF‐α therapy for orofacial granulomatosis

J Oral Pathol Med (2011) 40 : 14–19 Background: Orofacial granulomatosis (OFG) can be challenging to treat and experience with anti‐TNF‐α therapy is limited. We report our experience with infliximab (IFX) and adalimumab (ADA) for OFG in 14 patients, the largest reported series to date. Methods: A review of patients receiving induction and maintenance IFX for OFG +/? Crohn’s disease (CD) for active oral disease failing other therapies was performed. Clinical response defined by global physician assessment, aided by oral disease activity scores, was assessed at 2 months, 1 and 2 years. ADA was considered for patients failing IFX. Adverse events were recorded. Predictors of need for anti‐TNF‐α therapy were determined by comparison with OFG patients not requiring anti‐TNF‐α from our overall OFG database (n = 207). Results: Fourteen patients (9 men) were treated with IFX [OFG only (n = 7), OFG with CD (n = 7)]. Nine patients received concomitant immunosuppression. Median duration of treatment was 18 months. Short‐term response was achieved in 10/14 (71%) patients. Eight of 14 (57%) and 4/12 (33%) patients remained responsive at 1 and 2 years, respectively. Two patients who failed IFX responded to ADA. Factors predicting need for anti‐TNF‐α therapy were oral sulcal involvement, intestinal CD and a raised C‐reactive protein (CRP). Oral sulcal involvement predicted response at 1 and 2 years. Intestinal CD did not predict response. The only significant adverse event was an IFX infusion reaction. Conclusion: IFX provided good short‐term response for most OFG patients; however, a significant proportion lost response long term. Adverse events were uncommon. Patients failing IFX may respond to ADA.     

A Sialidase‐Deficient Porphyromonas gingivalis Mutant Strain Induces Less Interleukin‐1β and Tumor Necrosis Factor‐α in Epi4 Cells Than W83 Strain Through Regulation of c‐Jun N‐Terminal Kinase Pathway

Background: Porphyromonas gingivalis is one of the major periodontal pathogens. In a previous study, a mouse abscess model showed that sialidase deficiency of P. gingivalis weakened its virulence, but the mechanism behind this observation remains unknown. Methods: A sialidase‐deficient mutant strain (△PG0352) and a complemented strain (com△PG0352) were constructed. Epi4 cells were stimulated by wild‐type strain P. gingivalis W83, △PG0352, or com△PG0352. Real‐time polymerase chain reaction was carried out to detect expression of virulent genes in P. gingivalis and interleukin (IL)‐1β, IL‐6, IL‐8, and tumor necrosis factor (TNF)‐α in epi4 cells. Activities of sialidase, gingipains, and lipopolysaccharide (LPS) were compared among the different P. gingivalis strains. Levels of IL‐1β and TNF‐α in the epi4 cells supernatant were detected by enzyme‐linked immunosorbent assay and levels of p38, extracellular signal‐regulated kinase, c‐Jun N‐terminal kinase (JNK), and phospho‐c‐Jun were detected by western blotting. Results: Compared with P. gingivalis W83 and com△PG0352, activities of Kgp and Rgp gingipains and amount of LPS decreased in △PG0352, whereas there were no differences in LPS activity among these three strains. Level of phospho‐JNK was lower in epi4 cells stimulated by △PG0352. △pG0352 induced less IL‐1β and TNF‐α and more IL‐8 in epi4 cells; differences in IL‐1β and TNF‐α could not be detected after JNK blocking. Conclusion: A sialidase‐deficient P. gingivalis mutant strain induces less IL‐1β and TNF‐α in epi4 cells than W83 strain through regulation of JNK pathway.     

Elevated MicroRNA‐128 in Periodontitis Mitigates Tumor Necrosis Factor‐α Response via p38 Signaling Pathway in Macrophages

Background: Periodontitis is a chronic inflammatory disease resulting from an inflammatory response to subgingival plaque bacteria, including Porphyromonas gingivalis. MicroRNA (miRNA) is a current focus in regulating the inflammatory processes. In this study, the inflammatory miRNA expression in gingival tissues of patients with periodontitis and of healthy individuals is compared, and its role in regulating the inflammatory response is examined. Methods: Gingival tissues from patients with periodontitis and healthy individuals were collected for miRNA microarray. THP‐1 and CA9‐22 cells were challenged with P. gingivalis, and miRNA expression was determined by real‐time polymerase chain reaction. Target genes for miRNA were predicted using TargetScanHuman database, and miRNA gene expressions were reviewed using public databases. For the functional study, THP‐1 cells were transfected with a miRNA‐128 mimic, and target gene expression was compared with THP‐1 cells challenged with P. gingivalis. For the tolerance test, THP‐1 cells transfected with miRNA‐128 mimic were treated with phorbol 12‐myristate 13‐acetate (PMA) or paraformaldehyde (PFA)‐fixed Escherichia coli. Tumor necrosis factor (TNF)‐α production was determined by enzyme‐linked immunosorbent assay, and mitogen‐activated protein kinase (MAPK) protein phosphorylation was determined by Western blot. Results: Gingival tissues from patients with periodontitis showed increased expression of miRNA‐128, miRNA‐34a, and miRNA‐381 and decreased expression of miRNA‐15b, miRNA‐211, miRNA‐372, and miRNA‐656. THP‐1 cells and CA9‐22 cells challenged with P. gingivalis showed increased miRNA‐128 expression. Among the predicted miRNA‐128 target genes, several genes that are involved in MAPK signaling pathway showed similar gene expression pattern between P. gingivalis challenge and miRNA‐128 mimic transfection. In THP‐1 cells transfected with miRNA‐128 mimic, TNF‐α production was lower, and phosphorylation of p38 was inhibited when challenged with PMA or PFA‐fixed E. coli. Conclusion: miRNA‐128 may be involved in mitigating the inflammatory response induced by P. gingivalis in periodontitis.     

Significance of elevated gingival crevicular fluid tumor necrosis factor‐α and interleukin‐8 levels in chronic hemodialysis patients with periodontal disease

Da? A, F?rat ET, Kadiro?lu AK, Kale E, Y?lmaz ME. Significance of elevated gingival crevicular fluid tumor necrosis factor‐α and interleukin‐8 levels in chronic hemodialysis patients with periodontal disease. J Periodont Res 2010; 45: 445–450. © 2010 John Wiley & Sons A/S Background and Objective: The prevalence of chronic renal disease in industrialized countries is increasing, and chronic renal disease and periodontitis can have significant, reciprocal effects. The aim of this study was to evaluate the associations between specific clinical parameters and the levels of tumor necrosis factor‐α (TNF‐α) and interleukin‐8 (IL‐8) in the gingival crevicular fluid of hemodialysis (HD) patients with periodontal disease. Material and Methods: Forty‐three HD patients and 43 systemically healthy subjects were enrolled in this study. Plaque index (PI), gingival index (GI) and pocket depth were used to determine periodontal status. Venous blood samples were obtained from each patient in the morning before the dialysis session and analyzed to determine the levels of inflammatory, biochemical and hematological parameters. Gingival crevicular fluid was collected from all subjects, and the levels of TNF‐α and IL‐8 were determined in the gingival crevicular fluid samples. Results: The following results were obtained from HD patients and controls: TNF‐α (pg/mL), 31.40 ± 1.46 and 3.06 ± 0.15 (p < 0.001); IL‐8 (pg/mL), 90.98 ± 94.03 and 35.05 ± 16.86 (p < 0.001); PI, 1.69 ± 1.02 and 0.04 ± 0.02 (p < 0.001); GI, 0.82 ± 0.06 and 0.04 ± 0.02 (p < 0.001); and pocket depth, 2.23 ± 0.63 and 1.51 ± 0.05 (p < 0.001), respectively. In addition, there were positive correlations between TNF‐α and PI (r = 0.642, p < 0.001), between TNF‐α and GI (r = 0.565, p < 0.001), between TNF‐α and pocket depth (r = 0.522, p < 0.001), between IL‐8 and PI (r = 0.402, p = 0.002), between IL‐8 and GI (r = 0.396, p = 0.002), and between IL‐8 and pocket depth (r = 0.326, p = 0.012). There were negative correlations between albumin and PI (r = ?0.491, p < 0.001), albumin and GI (r = ?0.406, p < 0.001), albumin and pocket depth (r = ?0.464, p < 0.001) and albumin and CRP (r = ?0.467, p = 0.002) and between the gingival crevicular fluid levels of TNF‐α and IL‐8, TNF‐α and hemoglobin (r = ?0.745, p < 0.001; r = ?0.285, p < 0.05) (respectively). Conclusion: The levels of TNF‐α and IL‐8 in gingival crevicular fluid were significantly higher in HD patients than in controls. There were strong, positive correlations between clinical periodontal parameters and the levels of inflammatory cytokines in gingival crevicular fluid from the HD patients.     

Flutamide inhibits nifedipine‐ and interleukin‐1β‐induced collagen overproduction in gingival fibroblasts

Lu H‐K, Tseng C‐C, Lee Y‐H, Li C‐L, Wang L‐F. Flutamide inhibits nifedipine‐ and interleukin‐1β‐induced collagen overproduction in gingival fibroblasts. J Periodont Res 2010; 45: 451–457. © 2010 John Wiley & Sons A/S Background and Objective: To understand the role of the androgen receptor in gingival overgrowth, the effects of flutamide on interleukin‐1β‐ and nifedipine‐induced gene expression of connective tissue growth factor (CTGF/CCN2) and collagen production in gingival fibroblasts were examined. Material and Methods: Gingival fibroblasts from healthy subjects and patients with dihydropyridine‐induced gingival overgrowth (DIGO) were used. Confluent cells were treated with nifedipine, interleukin‐1β or both. The mRNA expression was examined using real‐time polymerase chain reaction, and the concentration of total soluble collagen in conditioned media was analysed by Sircol Collagen Assay. In addition, the protein expressions of androgen receptor, CTGF/CCN2 and type I collagen in gingival tissue were determined by western blot. Results: Interleukin‐1β was more potent than nifedipine in stimulating CTGF/CCN2 and procollagen α1(I) mRNA expression, and there was an additive effect of the two drugs. Healthy cells exhibited an equal or stronger response of procollagen α1(I) than those with DIGO, but DIGO cells displayed a stronger response in the secretion of soluble collagen in the same conditions. Flutamide, an androgen receptor antagonist, inhibited stimulation by nifedipine or interleukin‐1β. Additionally, the protein expressions of androgen receptor and type I collagen were higher in DIGO gingival tissue than those in healthy gingival tissue. Conclusion: The data suggest that both nifedipine and interleukin‐1β play an important role in DIGO via androgen receptor upregulation and that gingival overgrowth is mainly due to collagen accumulation. Flutamide decreases the gene expression and protein production of collagen from dihydropyridine‐induced overgrowth cells.     

MAPKs, activator protein-1 and nuclear factor-κB mediate production of interleukin-1β-stimulated cytokines, prostaglandin E₂ and MMP-1 in human periodontal ligament cells

Murayama R, Kobayashi M, Takeshita A, Yasui T, Yamamoto M. MAPKs, activator protein‐1 and nuclear factor‐κB mediate production of interleukin‐1β‐stimulated cytokines, prostaglandin E ₂ and MMP‐1 in human periodontal ligament cells. J Periodont Res 2011; 46: 568–575. © 2011 John Wiley & Sons A/S Background and Objective: Determination of the interleukin‐1 (IL‐1) signaling cascades that lead to the production of various inflammatory mediators and catabolic factors may clarify attractive targets for therapeutic intervention for periodontitis. We comprehensively assessed the involvement of MAPKs, activator protein‐1 (AP‐1) and nuclear factor‐κB (NF‐κB) in IL‐1β‐induced production of interleukin‐6 (IL‐6), interleukin‐8 (IL‐8), prostaglandin E₂ (PGE₂) and MMP‐1 in human periodontal ligament cells. Material and Methods: Human periodontal ligament cells were pretreated with an inhibitor for each of the MAPKs or NF‐κB and subsequently treated with IL‐1β. Following treatment, phosphorylation of three types of MAPK (ERK, p38 MAPK and c‐Jun N‐terminal kinase), IκB kinase (IKK) α/β/γ and IκB‐α, as well as the DNA binding activity of AP‐1 and NF‐κB and the production of IL‐6, IL‐8, PGE₂ and MMP‐1, were determined by western blotting, a gel mobility shift assay and ELISA, respectively. Results: The three MAPKs, simultaneously activated by IL‐1β, mediated the subsequent DNA binding of AP‐1 at various magnitudes, while IKKα/β/γ, IκB‐α and NF‐κB were also involved in the IL‐1 signaling cascade. Furthermore, IL‐1β stimulated the production of IL‐6, IL‐8, PGE₂ and MMP‐1 via activation of the three MAPKs and NF‐κB, because inhibitors of these significantly suppressed the IL‐1β‐stimulated production of these factors. Conclusion: Our results strongly suggest that MAPK, AP‐1 and NF‐κB mediate the IL‐1β‐stimulated synthesis of IL‐6, IL‐8, PGE₂ and MMP‐1 in human periodontal ligament cells. Therefore, inhibition of activation of MAPK, AP‐1 and/or NF‐κB may lead to therapeutic effects on progression of periodontitis.     

Scavenger receptor A is expressed by macrophages in response to Porphyromonas gingivalis,and participates in TNF‐α expression

Introduction: Porphyromonas gingivalis is a periodontopathic bacterium closely associated with generalized aggressive periodontal disease. Pattern recognition receptors (PRRs) participate in host response to this organism. It is likely that PRRs not previously recognized as part of the host response to P. gingivalis also participate in host response to this organism. Methods and Results: Employing qRT‐PCR, we observed increased msr1 gene expression at 2, 6, and 24 h of culture with P. gingivalis strain 381. Flow cytometry revealed increased surface expression of SR‐A protein by the 24 h time point. Macrophages cultured with an attachment impaired P. gingivalis fimA‐ mutant (DPG3) expressed intermediate levels of SR‐A expression. Heat‐killed P. gingivalis stimulated SR‐A expression similar to live bacteria, and purified P. gingivalis capsular polysaccharide stimulated macrophage SR‐A expression, indicating that live whole organisms are not necessary for SR‐A protein expression in macrophage response. As SR‐A is known to play a role in lipid uptake by macrophages, we tested the ability of low‐density lipoprotein (LDL) to influence the SR‐A response of macrophages to P. gingivalis, and observed no effect of LDL on P. gingivalis‐elicited SR‐A expression. Lastly, we observed that SR‐A knockout (SR‐A^?/?) mouse macrophages produced significantly more tumor necrosis factor (TNF)‐α than wild type mouse macrophages cultured with P. gingivalis. Conclusion: These data identify that SR‐A is expressed by macrophages in response to P. gingivalis, and support that this molecule plays a role in TNF‐α production by macrophages to this organism.     

Interleukin‐1α stimulation in monocytes by periodontal bacteria: antagonistic effects of Porphyromonas gingivalis

Periodontal pathogenic bacteria are associated with elevated levels of interleukin‐1α (IL‐1α) but it is unclear if all species can induce cytokine production equally. Porphyromonas gingivalis may be able antagonize IL‐1α induced by other species through the activity of its proteases or lipopolysaccharide (LPS). Monomac‐6 cells and primary human monocytes were treated with culture supernatants from Porphyromonas gingivalis, Fusobacterium nucleatum, Campylobacter rectus, Actinobacillus actinomycetemcomitans, Prevotella intermedius, Veillonella atypical and Prevotella nigrescens. IL‐1α protein levels were measured after 6 h of incubation. In addition, monocytes were co‐stimulated with supernatants from P. gingivalis and other bacteria. The role of P. gingivalis proteases was tested using Arg‐X and Lys‐X mutant strains. The role of LPS was investigated using purified P. gingivalis LPS and polymixin depletion. All species tested induced significant IL‐1α production, but P. gingivalis was the weakest. Co‐stimulation of monocytes with P. gingivalis antagonized the ability of other bacterial species to induce IL‐1α production. This effect was at its greatest with C. rectus (resulting in a 70% reduction). Gingipain mutant strains and chemical inhibition of protease activity did not reduce antagonistic activity. However, 100 ng/ml of P. gingivalis LPS can reproduce the antagonistic activity of P. gingivalis culture supernatants. Periodontitis‐associated bacterial species stimulate IL‐1α production by monocytes. P. gingivalis can antagonize this effect, and its LPS appears to be the crucial component. This study highlights the importance of mixed infections in the pathogenesis of periodontal disease because reduction of pro‐inflammatory cytokine levels may impair the ability of the host to tackle infection.     

Immunohistochemical analysis of interleukin‐1α, its type I receptor and antagonist in keratocystic odontogenic tumors

Background: Interleukin‐1α (IL‐1α) is thought to play a crucial role in the growth of keratocystic odontogenic tumors (KCOTs) in the jaw. The function of IL‐1α is regulated by the local levels of IL‐1α, its receptor and receptor antagonist (IL‐1Ra) in tissues. In this study, the expression of these proteins was investigated both before and after marsupialization in KCOTs. Methods: The expression of IL‐1α, IL‐1 receptor type I (IL‐1RI) and IL‐1Ra was detected immunohistochemically in 10 specimens of KCOTs. Results: IL‐1α was intensively expressed throughout the epithelium in all cases, while mild expression of IL‐1α was detected in the subepithelial layer endothelial cells and fibroblasts. Mild or intensive immunoreactivity for IL‐1RI was also observed in the epithelial cells in all cases, and in the endothelial cells and fibroblasts in five cases respectively. The expression of IL‐1Ra was detected in the epithelial cells in five cases, and in the endothelial cells and fibroblasts in three cases. After marsupialization, the immunoreactivity for IL‐1α and IL‐1RI in the epithelial cells decreased, while the immunoreactivity for IL‐1Ra in the epithelial cells increased. However, the immunoreactivity for IL‐1RI and IL‐1Ra in endothelial cells and fibroblasts did not change significantly. Conclusion: The effects of IL‐1α on the epithelial cells might be downregulated after marsupialization by changing the expression levels of IL‐1α, IL‐1RI and IL‐1Ra in the epithelium of KCOTs.     

Orthodontic Force Increases Interleukin‐1β and Tumor Necrosis Factor‐α Expression and Alveolar Bone Loss in Periodontitis

Background: The present study aims to evaluate the effects of orthodontic movement (OM) on the periodontal tissues of rats with ligature‐induced periodontal disease. Methods: Eighty‐eight rats were divided into four groups: 1) negative control (sham operated); 2) periodontal disease; 3) OM; and 4) periodontal disease followed by OM (OMP). Rats were sacrificed 3 hours or 1, 3, or 7 days after OM commencement. Bone volume fraction (BVF) and bone mineral density (BMD) were assessed in hemimaxillae by microcomputed tomography analysis. Expression of the proinflammatory cytokines interleukin (IL)‐1β and tumor necrosis factor (TNF)‐α were evaluated in gingival samples by quantitative polymerase chain reaction and enzyme‐linked immunosorbent assay, and in the furcation region by immunohistochemistry analysis (IHC). Results: The OMP group had lower BVF and BMD levels compared to the other groups at day 7 (P <0.05). Maximum messenger ribonucleic acid expression of both cytokines was observed in the OMP group at day 1 (P <0.05). In the same period, all proteins were expressed in high levels for all test groups compared to the control group. The number of cells positive for IL‐1β and TNF‐α by IHC was highest in the OMP group at day 1, with progressive reduction thereafter. Conclusion: The results suggest that OM acts synergistically with periodontal disease in periodontal breakdown through upregulation of proinflammatory cytokines.     

Tumor Necrosis Factor‐α and Interleukin (IL)‐1β, IL‐6, and IL‐8 Impair In Vitro Migration and Induce Apoptosis of Gingival Fibroblasts and Epithelial Cells,Delaying Wound Healing

Background: Multiple factors affect oral mucosal healing, such as the persistence of an inflammatory reaction. The present study evaluates effects of tumor necrosis factor (TNF)‐α and interleukin (IL)‐1β, IL‐6, and IL‐8 on epithelial cells (ECs) and human gingival fibroblasts (GFs) in vitro. Methods: GFs and ECs were seeded in 96‐well plates (1 × 10⁴ cells/well) in plain culture medium (Dulbecco’s modified Eagle’s medium [DMEM]) containing 1% antibiotic/antimycotic solution and 10% fetal bovine serum, and incubated for 24 hours. Both cell lines were exposed for 24 hours to the following cytokines: 1) TNF‐α (100 ng/mL); 2) IL‐1β (1 ng/mL); 3) IL‐6 (10 ng/mL); and 4) IL‐8 (10 ng/mL). All cytokines were diluted in serum‐free DMEM. Control cultures were exposed only to serum‐free DMEM. Effects of exposure to inflammatory cytokines were determined by means of: 1) apoptosis (anexin V); 2) cell migration (wound healing assay); 3) inflammatory cytokine synthesis (enzyme‐linked immunosorbent assay). Data were analyzed by Kruskal–Wallis and Mann–Whitney U tests (α = 0.05). Results: Increased apoptosis rates were noted when cells were exposed to inflammatory cytokines, except ECs exposed to IL‐1β. Cell migration was negatively affected by all inflammatory cytokines for both cell lines. ECs and GFs exposed to IL‐6 and IL‐8 significantly increased synthesis of TNF‐α and IL‐1β. Conclusions: Demonstrated results indicate negative effects of tested inflammatory cytokines on ECs and GFs, inducing apoptosis and impairing cell migration. These results can justify delayed oral mucosa healing in the presence of inflammatory reaction.