CD25+ B cells produced IL-35 and alleviated local inflammation during experimental periodontitis.

BACKGROUND AND OBJECTIVE: Host immunity is crucial during periodontal inflammations. B cells are considered to have a function of immunoregulation, and TLRs are considered to be crucial in this process. The present study illustrates the potential roles and rules of CD25+ B cells during periodontitis, especially its effect on regulating host IL-35 level and Th1, Th17, and Treg differentiation. MATERIAL AND METHODS: The proportion of local and systemic CD25+ B cell subpopulations from periodontitis models were identified by flow cytometry. To illustrate further mechanism, B cells were cultured with a different type of TLR activators. Expression of IL-10, IL-35, and TGF-ß was detected by ELISA and real-time PCR. We also set adoptive transfer models by using CD25+ B cells. Alveolar bone erosion, proportion of Th1, Th17, and Tregs, and levels of IFN-γ, TNF-α, IL-1ß, and IL-17 were identified. RESULT: Periodontitis induces more CD25+ B cell subpopulations and promotes their IL-10, IL-35, and TGF-ßproduction. TLR activators enhanced Breg proliferation and function. LPS+CpG obviously induced more CD25+ B cell differentiation and production of IL-10, IL-35, and TGF-ß. Adoptive transfer of CD25+ B cells reduces alveolar bone destruction and local Tregs, proportion, especially the local level of IFN-γ and IL-17. In addition, adoptive transfer of CD25+ B cells remedies the pathological change in the proportion of IL-1ß and Th1/Th17 in local lesions. We did not find any significant difference in peripheral blood, regardless of group and detected items. CONCLUSION: Results of the present study clarify that CD25+ B cells enlarged and produced more IL-10, IL-35 and TGF-ß during periodontitis, activation of TLR4 and TLR9 played crucial roles in this process. Also, CD25+ B cells alleviated periodontal inflammation and alveolar bone resorption. Our findings further expanded the potential of B cells during periodontitis.

Epidermal growth factor receptor signaling suppresses αvß6 integrin and promotes periodontal inflammation and bone loss.

In periodontal disease (PD), bacterial biofilms cause gingival inflammation, leading to bone loss. In healthy individuals, αvß6 integrin in junctional epithelium maintains anti-inflammatory transforming growth factor-ß1 (TGF-ß1) signaling, whereas its expression is lost in individuals with PD. Bacterial biofilms suppress ß6 integrin expression in cultured gingival epithelial cells (GECs) by attenuating TGF-ß1 signaling, leading to an enhanced pro-inflammatory response. In the present study, we show that GEC exposure to biofilms induced activation of mitogen-activated protein kinases and epidermal growth factor receptor (EGFR). Inhibition of EGFR and ERK stunted both the biofilm-induced ITGB6 suppression and IL1B stimulation. Furthermore, biofilm induced the expression of endogenous EGFR ligands that suppressed ITGB6 and stimulated IL1B expression, indicating that the effects of the biofilm were mediated by autocrine EGFR signaling. Biofilm and EGFR ligands induced inhibitory phosphorylation of the TGF-ß1 signaling mediator Smad3 at S208. Overexpression of a phosphorylation-defective mutant of Smad3 (S208A) reduced the ß6 integrin suppression. Furthermore, inhibition of EGFR signaling significantly reduced bone loss and inflammation in an experimental PD model. Thus, EGFR inhibition may provide a target for clinical therapies to prevent inflammation and bone loss in PD.

Antimicrobial effect of photodynamic therapy using sinoporphyrin sodium and 390-400 nm light-emitting diode on Porphyromonas gingivalis in vitro.

This study aims to investigate the effect of antimicrobial photodynamic therapy (a-PDT) using a novel combination of sinoporphyrin sodium (DVDMS) and light-emitting diode (LED) with a wavelength of 390-400 nm on Porphyromonas gingivalis in vitro. Absorption spectrum of DVDMS was determined by spectrometer for selecting suitable wavelength light source. The uptake of DVDMS by P. gingivalis was evaluated according to fluorescence intensity detected by a spectrometer. Then effects of DVDMS alone, 390-400 nm LED alone, and photodynamic therapy produced by 10, 20, 40, and 80 µg/mL DVDMS and 390-400 nm LED on the suspension of P. gingivalis were evaluated by counting the number of colony forming units (CFU) after incubation. In the experiment, the LED illumination time was 30, 60, 90, 120, 180, 240, and 360 s, respectively, and the corresponding energy density was 1, 2, 3, 4, 6, 8, and 12 J/cm2, respectively. According to the absorption spectrum of DVDMS, the 390-400-nm light emitted by the LED was selected as the light source. The fluorescence intensity of DVDMS on P. gingivalis increased significantly at 5 min, and with the extension of time, it decreased at 30 min. DVDMS alone did not produce a significant toxicity on P. gingivalis compared with PBS (p = 0.979). While 390-400 nm LED alone had a certain bactericidal effect on P. gingivalis, the bactericidal effect was more obvious as the light dose increased (p < 0.001). The effect of a-PDT produced by 20, 40, and 80 µg/mL DVDMS and 390-400 nm LED were significantly better than that of 390-400 nm LED alone (p < 0.05). Both DVDMS concentration and light dose could enchance the bactericidal effect. The strongest photo-killing effect was generated by 80 µg/mL DVDMS with 360 s illumination (energy density is 12 J/cm2), and the log reduction of bacteria was 5.69 ± 1.70. a-PDT using the combination of DVDMS with 390-400 nm LED shows promise as a new treatment modality for pathogens elimination in periodontal therapy.

Influence of photodynamic therapy on the periodontitis-induced bone resorption in rat.

This study aimed to evaluate the effects of toluidine blue-mediated photodynamic therapy (TB-PDT) on the periodontitis-induced bone resorption in periodontitis in rats. Periodontal disease was induced by cotton ligature around the right second maxillary molar in 64 rats. After 4 weeks, the rats were randomly divided into four groups: sterile saline solution (control group); laser therapy (laser group); TB (100 µg/mL); TB plus laser (0.15 W/cm2) irradiation every other day for 240 s (PDT group). All rats were euthanized at 15 days postoperatively. Eight gingival tissue samples were collected from each group. The expressions of receptor activator of nuclear factor kappa-Β ligand (RANKL) and osteoprotegerin (OPG) in gingival tissue samples were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The maxillae from the rest of the rats were taken for histological examination. In the PDT group, the analysis revealed less bone loss than in the control treatment (P < 0.05). No significant difference was found among the control group, TB group, and laser group (P > 0.05). Significantly higher and lower expressions of RANKL and OPG were revealed in the PDT group than that in control group, respectively (P < 0.01). When compared with the control group, the expression of RANKL was significantly reduced by 40.0% in periodontitis in rats treated with TB-PDT for 15 days (P < 0.01). The expression of OPG was increased in the PDT group with TB-PDT for 15 days, when compared with the control group (P < 0.05). TB-PDT treatment significantly reverses the abnormal expression of RANKL and OPG in periodontitis in rats.

Hematoporphyrin monomethyl ether mediated sonodynamic antimicrobial chemotherapy on porphyromonas gingivalis in vitro.

This study aimed to evaluate the efficacy of hematoporphyrin monomethyl ether (HMME)-mediated sonodynamic antimicrobial chemotherapy (SACT) on Porphyromonas gingivalis (P. gingivalis). P. gingivalis (ATCC 33277) was used in the present study. The bacterial suspension was randomly divided into five groups: Group 1 was incubated for 2 h in the dark with HMME in various concentrations (10, 20, 30 and 40 µg/mL). Then exposed to 1 MHz ultrasound frequency with 3 W/cm2 ultrasound intensity for 10 min. Group 2 was incubated with 40 µg/mL HMME and then irradiated with 2, 4, 6, 8 and 10 min ultrasonic time. Group 3 received different HMME concentration (10, 20, 30 and 40 µg/mL) treatment alone with no ultrasound as the HMME control group. Group 4 received ultrasound treatment alone in different ultrasonic time (2, 4, 6, 8 and 10 min) with no HMME as the ultrasound control group. Group 5 received no treatment as the no treatment control group. After the SACT, the bactericidal effect was determined by the colony forming unit assay. The intracellular content of reactive oxygen species (ROS) was detected using the laser scanning confocal microscope based on DCFH-DA. 4.7 lg reduction in CFU, When P. gingivalis was treated with ultrasound (3 W/cm2 for 10 min) at 40 µg/mL HMME concentration (P < 0.01). The intracellular ROS in SDT group had a significant difference in comparison with the no treatment control group (P < 0.01). HMME mediated SACT can be a potential antibacterial therapy to significantly inhibit P. gingivalis growth.

Inflammasome and cytokine expression profiling in experimental periodontitis in the integrin ß6 null mouse.

Epithelial αvß6 integrin participates in immune surveillance in many organs, including the gastrointestinal track. Expression of αvß6 integrin is reduced in the junctional epithelium of the gingiva in periodontal diseases, and mutations in the ITGB6 gene are associated with these diseases in humans and mice. The aim of this study was to unravel potential differences in the inflammatory responses in the periodontal tissues of FVB wild-type (WT) and ß6 integrin-null (Itgb6-/-) mice, using a ligature-induced periodontitis model and assessing inflammation, bone loss and expression profiles of 34 genes associated with periodontal disease. Using micro-CT and histology, we demonstrated more advanced inflammation and bone loss in the control and ligatured Itgb6-/- mice compared to the WT animals. Neutrophil and macrophage marker genes were significantly upregulated by ligation in both WT and Itgb6-/- mice while the expression of T-cell and B-cell markers was downregulated, suggesting acute-type of inflammation. Expression of inflammasome NLRP3-related genes Nlpr3 and Il1b was also significantly increased in both groups. However, the expression of Il18 was significantly lower in non-ligatured Itgb6-/- mice than in the WT mice and was further downregulated in both groups by the ligatures. IL-18 mediates many effects of the AIM2 inflammasome, including regulation of the microbiome. Interestingly, expression of Aim2 was significantly lower in both control and ligatured Itgb6-/- mice than in WT animals. Overall, ligature-induced periodontitis was associated with increased expression of pro-inflammatory cytokines, chemokines and osteoclastogenic regulatory molecules. Another significant difference between the Itgb6-/- and WT mice was that mRNA expression of the anti-inflammatory cytokine IL-10 was increased in ligatured WT mice but reduced in the Itgb6-/- mice. In conclusion, αvß6 integrin in junctional epithelium of the gingiva appears to positively regulate the expression of the AIM2 inflammasome and anti-inflammatory IL-10, thus providing protection against periodontal inflammation.

Porphyromonas gingivalis exacerbates ligature-induced, RANKL-dependent alveolar bone resorption via differential regulation of Toll-like receptor 2 (TLR2) and TLR4.

Toll-like receptors (TLRs) play a key role in the innate immune responses to periodontal pathogens in periodontal disease. The present study was performed to determine the roles of TLR2 and TLR4 signaling in alveolar bone resorption, using a Porphyromonas gingivalis-associated ligature-induced periodontitis model in mice. Wild-type (WT), Tlr2(-/-), and Tlr4(-/-) mice (8 to 10 weeks old) in the C57/BL6 background were used. Silk ligatures were applied to the maxillary second molars in the presence or absence of live P. gingivalis infection. Ligatures were removed from the second molars on day 14, and mice were kept for another 2 weeks before sacrifice for final analysis (day 28). On day 14, there were no differences in alveolar bone resorption and gingival RANKL expression between mice treated with ligation plus P. gingivalis infection and mice treated with ligation alone. Gingival interleukin-1ß (IL-1ß) and tumor necrosis factor alpha (TNF-α) expression was increased, whereas IL-10 expression was decreased in WT and Tlr2(-/-) mice but not in Tlr4(-/-) mice. On day 28, WT and Tlr4(-/-) mice treated with ligation plus P. gingivalis infection showed significantly increased bone loss and gingival RANKL expression compared to those treated with ligation alone, whereas such an increase was diminished in Tlr2(-/-) mice. Gingival TNF-α upregulation and IL-10 downregulation were observed only in WT and Tlr4(-/-) mice, not in Tlr2(-/-) mice. In all mice, bone resorption induced by ligation plus P. gingivalis infection was antagonized by local anti-RANKL antibody administration. This study suggests that P. gingivalis exacerbates ligature-induced, RANKL-dependent periodontal bone resorption via differential regulation of TLR2 and TLR4 signaling.

Bactericidal effects of hematoporphyrin monomethyl ether-mediated photosensitization against pathogenic communities from supragingival plaque.

Photodynamic antimicrobial chemotherapy (PACT) is proposed as a potential candidate to inactivate pathogens in localized infections due to the rapid evolution of bacterial resistance. The treatment modality utilizes nontoxic agents called photosensitizers and harmless visible light to generate reactive oxygen species which result in microbial cells' killing. Hematoporphyrin monomethyl ether (HMME) as a novel and affordable photosensitizer has been used in treating various clinical diseases for years, but few applications in infection. In this report, we studied the bactericidal effects of the HMME-mediated photodynamic reaction on the pathogenic microbes in supragingival plaque which can lead to many oral infectious diseases such as caries, gingivitis, and so on. Our findings demonstrated that HMME promoted an effective action in bacterial reduction with the application of laser energy. Moreover, the antimicrobial activities were dramatically enhanced as the HMME concentration and exposure time were increased, but reached a plateau when matched the appropriate agent concentration and illumination. It was found that the survival fraction of microorganisms is exponentially dependent on the product of HMME concentration and irradiation time. These promising results suggest the HMME may be an excellently cost-effective photosensitizing agent for mediating PACT in the treatment of supragingival plaque-related diseases. An optimized HMME concentration and irradiation time has been found to achieve the best results under our experimental conditions. The high HMME concentration matching short curative time, or vice versa, can achieve the similar therapeutic effect, which may provide more flexible treatment plans according to specific conditions.

Effect of super activated platelet lysate on cell proliferation, repair and osteogenesis.

BACKGROUND: Platelet lysate (PL) is considered as an alternative to fetal bovine serum (FBS) and facilitates the proliferation and differentiation of mesenchymal cells. OBJECTIVE: The aim of this study is to explore whether super activated platelet lysate (sPL), a novel autologous platelet lysate, has the ability to inhibit inflammation and promote cell proliferation, repair and osteogenesis as a culture medium. METHODS: Different concentrations of sPL on human fetal osteoblastic 1.19 cell line (hFOB1.19) proliferation and apoptotic repair were investigated; And detected proliferative capacity, inflammatory factor expressions and osteogenic differentiation of human dental pulp cells (hDPCs) stimulated by LPS under 10% FBS and 5% sPL mediums. RESULTS: sPL promoted hFOB1.19 proliferation and had repairing effects on apoptotic cells. No significant difference in proliferation and IL-1α, IL-6 and TNF-α expressions of hDPCs in FBS and sPL medium stimulated by LPS. hDPCs in sPL osteogenic medium had higher osteogenic-related factor expressions and ALP activity. LPS promoted osteogenic-related factor expressions and ALP activity of hDPCs in FBS osteogenic medium, but opposite effect showed in sPL medium. CONCLUSION: sPL promoted osteoblast proliferation and had restorative effects. Under LPS stimulation, sPL did not promote hDPCs proliferation or inhibit inflammation. sPL promotes osteogenic differentiation of hDPCs.

The impact of IGF-1 on alveolar bone remodeling and BMP-2 expression in orthodontic tooth movement in diabetic rats.

BACKGROUND: Orthodontic tooth movement is linked to alveolar bone reconstruction. OBJECTIVES: As a regulator of cell proliferation, insulin-like growth factor 1 (IGF-1) plays an important role in osteoporotic fracture healing. This study aims to investigate the effect of IGF-1 on alveolar bone remodeling in diabetic rats. MATERIAL AND METHODS: Sprague Dawley (SD) rats were randomly divided into 3 groups, including a control group, a model group established with streptozotocin (STZ) injection to prepare the diabetic rats (type 1 diabetes), and an IGF-1 group of diabetic rats receiving daily intraperitoneal injections of 1.0 mg/kg IGF-1. Nickel-titanium coil springs were used to pull the first molar forward to establish the model. The maxillary first to third molars and the surrounding alveolar bone were collected to measure tooth movement distance. Hematoxylin and eosin (H&E) staining was applied to detect the pathological changes in the periodontal tissue. Real-time polymerase chain reaction (PCR) and western blot were adopted to measure bone morphogenetic protein 2 (BMP-2) mRNA and protein expression. Enzyme-linked immunosorbent assays (ELISAs) were used to measure interleukin-1α (IL-1α) levels in the serum. RESULTS: The tooth movement distance was significantly decreased, BMP-2 expression was downregulated, and IL-lα levels were enhanced in the model group compared to the control group (p < 0.05). However, the tooth movement distance was increased, BMP-2 expression was increased, and IL-lα levels were reduced in the IGF-1 group compared to the model group (p < 0.05). Hematoxylin and eosin staining showed that alveolar bone destruction was attenuated in the IGF-1 group, while the new bone was not active in the model group. CONCLUSIONS: Diabetes can damage alveolar bone remodeling in orthodontic tooth movement. The IGF-1 promotes alveolar bone remodeling by inhibiting inflammation and upregulating BMP-2 expression.

Effects of Super-Activated Platelet Lysate on Early Healing of Tooth Extraction Sockets in Rats.

Purpose: To evaluate the effect of super-activated platelet lysate (sPL) on wound healing of tooth extraction sockets in rats. Methods: Rat models of the tooth extraction socket were established. Thirty-six rats were divided into control and sPL groups and sacrificed on days 7, 14, and 28 after tooth extraction. Bone formation in tooth extraction sockets were observed by microscopic computed tomography (micro-CT) and hematoxylin and eosin (HE) staining; osteoprotegerin (OPG), receptor activator of nuclear factor kappa-Β ligand (RANKL), interleukin 6(IL-6), and tumor necrosis factor-alpha (TNF-α) proteins were detected by immunohistochemistry; and chemokine and osteogenic gene expressions were detected by polymerase chain reaction (PCR). Results: sPL accelerated soft tissue wound healing in the extraction socket of rats. Micro-CT showed that the amount of bone formation and bone volume fraction were higher in the sPL group than the control 14 days after extraction. HE staining showed promotion of the formation of bony trabeculae by sPL in the apical third of the extraction socket 7 days after extraction and more mature and organized bony trabeculae in the sPL group than the control 14 days after extraction; mature bony trabeculae filling most of the fossa with lesser bone porosity in the socket in the sPL group than the control 28 days after extraction. Immunohistochemistry showed that sPL induced OPG expressions 7 and 14 days after tooth extraction but did not affect the RANKL expression while transiently promoting the IL-6 expression 7 days after extraction. PCR showed that sPL promoted chemokine expressions 7 and 14 days after extraction. The expressions of osteogenesis-related factors were higher in the sPL group than the control 7 and 28 days after extraction, while the opposite trend was observed 14 days after extraction. Conclusion: sPL has a transient pro-inflammatory effect and promotes soft tissue healing and bone formation during early wound healing of extraction sockets in rats.

Gingival curettage study comparing a laser treatment to hand instruments.

The purpose of this clinical study was to examine nonsurgical treatments of periodontal disease comparing a diode laser to subgingival curettage with conventional hand instruments. The study group comprised 18 patients with moderate periodontal degradation who were treated without local anesthesia. Each quadrant was randomly allocated in a split-mouth design either to treatment with a 810-nm diode laser using an energy of 2 W (test group) or to gingival curettage using hand instruments (control group). Clinical data, including plaque index (PI), gingival index (GI), sulcus bleeding index (SBI), pocket depth (PD), clinical attachment level (CAL) and visual analog scale (VAS) score were acquired prior to and 4 weeks after treatment. The treatment time for each tooth was also recorded. The results demonstrated a statistically significant reduction of the GI, SBI and PD and a significant gain in CAL in both groups after 4 weeks. However, there were no significant differences between the test and control groups for the above data. The score for the degree of treatment discomfort was significantly lower and the average treatment time was significantly less in the test group than in the control group. Diode laser subgingival curettage resulted in statistically significant improvements in PD, SBI, GI and CAL with less discomfort and treatment time compared to treatment with the hand instruments.

Antimicrobial photodynamic therapeutic effects of cationic amino acid-porphyrin conjugate 4i on Porphyromonas gingivalis in vitro.

BACKGROUND: Porphyromonas gingivalis (P. gingivalis) is considered to be among the principal pathogens in periodontal disease. The present study aimed to investigate the effect of antimicrobial photodynamic therapy (aPDT) mediated by cationic amino acid-porphyrin conjugate 4i on P. gingivalis METHODS: The uptake of 4i by P. gingivalis over different times of incubation was evaluated by optical density using a microplate reader. Laser radiation at λ=650nm-660nm with I =50 mW/cm2 at doses of 0, 3.0, 6.0, 9.0, and 12 J/cm2 was used for aPDT. A colony-counting method and confocal laser scanning microscopy (CLSM) were used to observe the neutralization of P. gingivalis. The fluorescent molecular probe 3'(p-hydroxyphenyl)-fluorescein and the reagent Singlet Oxygen Sensor Green were used to measure the quantities of •OH and 1O2 produced by 4i after irradiation with different light energies. RESULTS: The 4i conjugate was absorbed gradually by P. gingivalis, reaching a maximum at 30 min. A clear cytotoxic effect on P. gingivalis was observed with aPDT using 62.5 µM 4i, with colony counts dropping by a factor of 3.35 log10, indicating a sterilization rate of 99.95%. Light irradiation resulted principally in the production of • OHby 4i. A live/dead viability assay demonstrated substantial red fluorescence in P. gingivalis treated with aPDT. CONCLUSIONS: The results suggest that 4i-aPDT caused substantial cytotoxicity in P. gingivalis.

Super Activated Platelet Lysate, a Novel Autologous Platelet Lysate, Regulates the Expression of Inflammasome and Cytokine in the Experimental Periodontitis in Rats.

PURPOSE: The aim of the present study was to evaluate the expression of inflammasome and cytokine on experimental periodontitis with super activated platelet lysate (SPL) in rats. METHODS: Periodontitis was induced by submerging cotton ligatures on the right side of the maxillary second molar in 36 Wistar rats. The rats were divided into 3 groups randomly: the rats received no treatment (control group); local injection with sterile saline (ligature+saline group) and local injection with SPL (ligature+SPL group). After treatments, the alveolar bone level and inflammation of periodontal tissue were evaluated by micro-computed tomography (micro-CT) scanning and histological examination, respectively. The expression of inflammasome and cytokine was evaluated by real-time quantitative polymerase chain reaction (RT-qPCR) assay. RESULTS: Compared with the control group, the bone loss significantly increased by 0.9 mm in the ligature+saline group and 0.4 mm in the ligature+SPL group (P < 0.001). 0.5 mm reduction in the bone loss was founded in the ligature+SPL group compared with the ligature+saline group (P < 0.001). The gene expression of CCL2, CXCL2, IL-6, IL-18, IL-1α, IL-1ß, CXCL10, CXCL16, CCL5 was significantly reduced in the ligature+SPL group compared with the ligature+saline group (P < 0.05). Compared with the ligature+saline group, the expression for inflammasome NLRP3, AIM2, CASP1 was both downregulated in the ligature+SPL group (P < 0.05). CONCLUSION: Our present study demonstrated local injection of SPL regulated the expression of inflammasome and cytokine and had a visible effect of relieving inflammation in the experimental periodontitis in rats.

Evaluation of interleukin-10 producing CD19+ B cells in human gingival tissue.

OBJECTIVE: This study aimed to evaluate IL-10 producing CD19+ B cells and to examine the correlation between these cells and the expression levels of IL-1ß, TNF-α, RANKL, and IL-10 cytokines in the gingival tissues of individuals with and without chronic periodontitis. DESIGN: Data were obtained from 20 patients with chronic periodontitis and 10 healthy controls. The gingival samples were analyzed by immunofluorescence, while real-time PCR and enzyme-linked immunosorbent assays were performed to determine cytokine levels. RESULTS: The number of IL-10 producing CD19+ B cells and the expression levels of IL-10 were significantly higher in the inflamed gingival tissues than in the healthy tissues. A positive correlation between the expression levels of IL-10 and the number of IL-10 producing CD19+ B cells were observed. IL-1ß, TNF-α, and RANKL expression levels were significantly elevated in diseased gingivae compared to healthy tissues, and there was a positive correlation between the expression levels of these pro-inflammatory cytokines and the number of IL-10 producing CD19+ B cells. CONCLUSION: While IL-10 producing CD19+ B cells are present in the gingival tissues of patients with periodontal disease and of those with a healthy periodontium, the diseased gingival tissues had a much greater number of these cells than the healthy. The mRNA and protein levels of IL-10, IL-1ß, and RANKL, as well as mRNA levels of TNF-α, were positively correlated with the number of IL-10 producing CD19+ B cells, which highlights the importance of these factors in the development and progression of periodontitis.

Low-Intensity Ultrasound Combined with Hematoporphyrin Monomethyl Ether in the Treatment of Experimental Periodontitis in Rats.

Objectives. This study aims to evaluate the efficacy of hematoporphyrin monomethyl ether- (HMME-) mediated sonodynamic therapy (SDT) on experimental periodontal disease in rats. Methods. Periodontal disease was induced by submerging ligatures at the first maxillary molar subgingival region in forty-eight male SD rats. After 30 days, the ligatures were removed. The rats were randomly allocated into four groups; the experimental SDT group was treated through hypodermic injection of 40 µg/mL HMME and 3 W/cm2 low-intensity ultrasound irradiation (1 MHz, 600 s). Those in control groups received 40 µg/mL HMME alone (control 1 group) or 3 W/cm2 ultrasound irradiation alone (control 2 group) or were subjected to neither HMME nor ultrasound (control 3 group). After 10 days of treatment, all rats were euthanized, the maxilla was obtained for histological examination, and the alveolar bone level was evaluated by histometric analysis. Results. The control groups showed more bone loss (P < 0.05) after 10 days of treatment than the SDT group. There is no significant difference among the control groups (P > 0.05). Conclusions. HMME mediated SDT was an effective therapy of experimental periodontal tissue in rats.

Sonodynamic effect of hematoporphyrin monomethyl ether on ligature-induced periodontitis in rats.

OBJECTIVES: The aim of this study was to perform a histological evaluation of sonodynamic therapy (SDT) of hematoporphyrin monomethyl ether (HMME) on artificially induced periodontal disease in rats. METHODS: Submerging ligatures were placed at the subgingival region of the first maxillary molar in rats. Eighty rats were randomly assigned into four groups: group 1 received no treatment; group 2 was subjected to 50 µg/mL HMME alone; group 3 was treated with low-intensity ultrasound alone (1 W/cm(2)); and group 4 was treated with 50 µg/mL HMME plus ultrasound irradiation (1 MHz, 30 minutes). Ten rats in each group were euthanized at 7 and 15 days, and periodontal tissue samples were taken for histological examination. RESULTS: The animals treated by SDT showed less bone loss (P<0.05) at all experimental periods than the other three groups. No significant differences were found between the control and HMME groups (P>0.05). CONCLUSION: Our results suggest that HMME-mediated SDT can effectively alleviate the periodontal tissue destruction in artificially induced periodontitis in rats. Hence, SDT may have good clinic potential as a noninvasive treatment of periodontal diseases.

[Effects of Porphyromonas gingivalis infection on intercellular adhesion molecule-1 expression in rat vascular smooth muscle cells].

OBJECTIVE: To observe the effects of Porphyromonas gingivalis (P. gingivalis) ATCC 33277 infection on expression of intercellular adhesion molecule-1 (ICAM-1) in rat vascular smooth muscle cells(VSMC). METHODS: An infection model of rat VSMC invaded by P. gingivalis was established in vitro. The mRNA of ICAM-1 was measured through reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Compared with the control group, an apparent and statistically significant increase in expression of ICAM-1 mRNA was observed after 8, 16, and 24 h in P. gingivals-infected rat VSMC (P<0.05). The expression reached its peak at 16 h. Statistically significant differences were observed in the 8 h group and in the other two experimental groups (P<0.05). CONCLUSION: Infection of P. gingivals in rat VSMC can cause increased expression of ICAM-1, which may have an important function in the progression of atherosclerosis.

Periodontal ligament remodeling and alveolar bone resorption during orthodontic tooth movement in rats with diabetes.

BACKGROUND: Pathological displacement of teeth caused by periodontitis-related bone loss in patients with diabetes is often corrected with orthodontic treatments. However, recovery from orthodontic therapy is often delayed for unclear reasons. This study explored effects of streptozotocin-induced diabetes in rats on protein expression involved in remodeling of the periodontal ligament (PDL) and alveolar bone during orthodontic tooth movement. METHODS: Forty-eight Sprague-Dawley rats were randomly divided into two experimental groups: "normal" and "diabetes" (n = 24 each). Diabetes was induced by a single dose of streptozotocin (65 mg/kg). Animals were euthanized at 3, 7, and 14 days after orthodontic induction. Changes in expression of collagen type I (Col-I), matrix metalloproteinase type 1 (MMP-1), and tissue inhibitor of MMP-1 (TIMP-1) were measured immunohistochemically in the pressure side. Col-I and collagen type III (Col-III) fibers were assessed by picrosirius red staining in the tension side. Osteoclasts were observed on the surface of the alveolar bone. RESULTS: Diabetes increased expression of MMP-1 and Col-III and decreased expression of Col-I in PDL. After the orthodontic induction, osteoclast action was delayed, and higher Col-III/Col-I and MMP-1/TIMP-1 ratios persisted in the diabetes group compared with the normal group. The ratio of MMP-1/TIMP-1 in the diabetes group reached a peak on Day 7, whereas the ratio remained at near control levels in the normal group. The diabetes group appeared to have worse recovery from damage caused by orthodontic movement. CONCLUSIONS: Under mechanical forces, diabetes prolonged duration of degradation of PDL and remodeling of PDL and resorption of alveolar bone.