シシュウビョウ ト コウサンカ ブッシツ

Reactive oxygen species (ROS), which include super oxide (O2-・), hydroxyl radical (HO・), singlet oxygen (1O2) and hydrogen peroxide (H2O2), are products of normal cellular metabolism. ROS are well recognized for playing a dual role as both deleterious and beneficial effects to living systems. The harmful effects occur in biological systems when there is a overproduction of ROS on one side and a lack of enzymatic or non-enzymatic antioxidants on the other side. Furthermore, oxidative stress results from the metabolic reactions which use oxygen and represents a disturbance in the equilibrium status of antioxidants in living organisms. The excess of ROS can damage proteins, cellular lipids, and DNA inhibiting their normal function. Therefore, oxidative stress has been implicated in a number of human diseases as well as periodontitis. Recently, clinical studies have noted that the patients of periodontitis have elevated blood levels of oxidative stress compared to periodontally healthy subjects in the cross sectional design. Additionally, the increased oxidative stress is significantly associated with the progression of periodontitis. In longitudinal study, periodontal treatment decreases oxidized low density lipoprotein levels and total oxidative status in the blood of chronic periodontitis patients. In recent years, many compounds and plant extracts have considerable antioxidant activity, and applied to animal experimental periodontitis models. Investigations provided their possibility for preventive effects on periodontitis. For example, polyphenol including flavonoid revealed both antioxidant and anti-inflammation effect, suppressing the progression of periodontitis by decreasing gingival oxidative stress. In particular, rats were given resveratrol as drinking water and experimental periodontitis was induced in our study. As a result, resveratrol intake relieved alveolar bone resorption and activated the Sirtuin1 / AMP-activated protein kinase and the nuclear factor E2-related factor 2 / antioxidant defense pathways in inflamed gingival tissues. Moreover, resveratrol improved the systemic levels of 8-hydroxy-2’-deoxyguanosine, dityrosine, nitric oxide metabolism, nitrotyrosine, and proinflammatory cytokines. We concluded that oral administration of antioxidants could prevent the progression of experimental periodontitis and improve systemic oxidative stress

Molecular analysis for bacterial contamination

Bacterial contamination in dental unit waterlines (DUWLs) was evaluated by molecular techniques in addition to the conventional culture method. Water samples (n=8) from DUWLs were investigated for heterotrophic bacteria by culture method using R2A agar. The selected bacterial antibiotic-resistance genes and Legionella species-specific 16SrDNA were identified by PCR. The profiles of bacterial contamination in DUWLs were further identified by PCR-DGGE. In this study, no antibiotic-resistant or Legionella genes were detected. Polycyclic aromatic hydrocarbon-degrading bacterium, Novosphingobium sp. was the most prevalent in DUWLs. Conventional PCR and PCR-DGGE were shown to be potentially useful for monitoring of bacterial contamination in DUWLs

サンカ ストレス ト シシュウビョウ

Periodontitis is a term used to describe a chronic inflammatory disease, caused by subgingival plaque biofilm, that leads to the loss of tissues supporting the root surfaces and adjacent alveolar bone, which ultimately results in tooth loss. It is believed that while the primary etiological agent is specific, a majority of periodontal tissue destruction is caused by an inappropriate host response to those microorganisms and their products. More specifically, a loss of homeostatic balance between reactive oxygen species (ROS) and antioxidant defense systems, which protect and repair vial tissues, cells, and molecular components, are believed to be responsible. A paradigm shift in our understanding of the importance of ROS and antioxidant power to human biology over the last decade came from the realization of vial and ubiquitous transcription factors. ROS are products of normal cellular metabolism; however, excessive products of ROS oxidize proteins, lipids, and DNA, resulting in tissue damage. Studies have shown that systemic increases in ROS are involved in the pathogenesis of periodontitis. When periodontitis develop, ROS produced in the periodontal lesion diffuse into the blood stream, resulting in the oxidation of circulating oxidative stress. For instance, previous animal studies in a rat periodontal model suggested that experimental periodontitis induced oxidative damage by increasing circulating oxidative stress. In addition, a positive association has been shown to exist between oxidative status and clinical attachment level in the maintenance phase of chronic periodontitis patients. These results suggest that high oxidative status in plasma could have affected the rate of progression of periodontal disease in the past. Furthermore, patients with chronic periodontitis showed higher levels of circulating oxidized low-density lipoproteins, C-reactive proteins, and oxidative stress than healthy subjects. Non-surgical periodontal treatment was effective in improving periodontal health and decreasing oxidized low-density lipoprotein and C-reactive protein, which were positively associated with a reduction in circulating oxidative stress. In patients with chronic periodontitis, a reduction in periodontal inflammation by non-surgical periodontal treatment might be beneficial in preventing systemic disease by decreasing circulating oxidative stress. Furthermore, increased serum levels of ROS following periodontitis may influence the rate of progression of systemic diseases. Hepatocellular carcinoma patients with chronic periodontitis had a higher circulating ROS level and progression of cancer than patients without periodontitis. Therefore, increased ROS levels following periodontitis may be detrimental to hepatic health

Bacterial-contamination Monitoring

Bacterial contamination of dental unit waterlines (DUWLs) was evaluated by using ATP-bioluminescence analysis and conventional culture method. Water samples (n=44) from DUWLs were investigated for heterotrophic bacteria by culture on R2A agar, which ranged from 1.4×103 to 2.7×105 CFU/mL. The ATP-bioluminescence results for DUWL samples were ranged from 6 to 1189 RLU and obtained within one minutes. These results were well correlated with the culture results (r=0.727-0.855). We conclude that differences in the bacterial contamination of each water supply were confirmed by the ATP-bioluminescence assay. This method would be potentially useful for rapid and simple monitoring of DUWL bacterial contamination

Use of ATP bioluminescence to survey the spread of aerosol and splatter during dental treatment

Aerosol and splatter produced during dental treatment (ultrasonic scaling and professional mechanical tooth cleaning) are potential sources of infection. Contamination patterns on the operators’ masks, goggles, chests and gowned right arms, and on the patients’ goggles, before and after dental treatment were investigated by using ATP bioluminescence analysis. Contamination on every surface tested increased significantly after dental treatment. Maximum contamination was found on patients’ goggles. Aerosol and splatter produced during dental treatment thus have the potential to spread infection to operators and patients. ATP bioluminescence is a useful tool for monitoring surface contamination

ヒト角化上皮細胞における5-FU誘発性酸化ストレスおよび炎症応答に対するresveratrolの保護効果

Although 5-fluorouracil (5-FU) is currently used as an anti-cancer chemotherapy, adverse effects such as oral mucositis potentially limit its clinical application. Additionally, the prevention of 5-FU-induced side effects are scarce. Resveratrol is known to decrease oxidative damage and inflammation. In this study, we examined the protective effects of resveratrol on 5-FU-induced oxidative stress and inflammatory responses in normal human keratinocytes (HaCaT cell) as in vitro oral mucositis model. HaCaT cells were exposed to 5-FU and simultaneously treated with resveratrol. The effects of resveratrol on 5-FU-induced cytotoxicity were evaluated using cell viability assay. The production of reactive oxygen species (ROS) was measured using a fluorescence spectrophotometer. The effects of resveratrol on nuclear factor erythroid 2-related factor 2 (Nrf2), silent information regulator transcript-1 (SIRT-1), and nuclear factor kappa B (NF-κB) signaling and inflammatory cytokine expression were examined. Resveratrol suppressed 5-FU-induced overproduction of ROS by upregulating anti-oxidant defense genes through Nrf2 activation and SIRT-1 expression. Concerning inflammatory responses, resveratrol suppressed the 5-FU-induced expression of pro-inflammatory cytokines via NF-κB nuclear translocation. Conversely, N-acetylcysteine reduced ROS levels without affecting the expression of pro-inflammatory cytokines. Resveratrol might be useful for preventing 5-FU-induced adverse effects by activating anti-oxidant and anti-inflammatory responses

Hydrogen-Rich Water Intake Accelerates Oral Palatal Wound Healing via Activation of the Nrf2/Antioxidant Defense Pathways in a Rat Model

The wound healing process attempts to restore the integrity and function of the injured tissue. Additionally, proinflammatory cytokines, growth factors, and oxidative stress play important roles in wound healing. The aim of this study was to determine whether hydrogen-rich water intake induces the activation of the Nrf2/antioxidant defense pathway in rat palatal tissue, thereby reducing systemic oxidative stress and proinflammatory cytokine levels and promoting healing-associated genes. A circular excisional wound was created in the oral palatal region, and the wound healing process was observed.The rats were divided into two experimental groups in which either hydrogen-rich water or distilled water was consumed. In the drinking hydrogen-rich water, the palatal wound healing process was accelerated compared to that in the control group. As molecular hydrogen upregulated the Nrf2 pathway, systemic oxidative stresses were decreased by the activation of antioxidant activity. Furthermore, hydrogen-rich water intake reduced proinflammatory cytokine levels and promoted the expression of healing-associated factors in rat palatal tissue. In conclusion, hydrogen-rich water intake exhibited multiple beneficial effects through activation of the Nrf2/antioxidant defense pathway.The results of this study support the hypothesis that oral administration of hydrogen-rich water benefits the wound healing process by decreasing oxidative stress and inflammatory responses

Hydrogen-Rich Water Intake Accelerates Oral Palatal Wound Healing via Activation of the Nrf2/Antioxidant Defense Pathways in a Rat Model

The wound healing process attempts to restore the integrity and function of the injured tissue. Additionally, proinflammatory cytokines, growth factors, and oxidative stress play important roles in wound healing. The aim of this study was to determine whether hydrogen-rich water intake induces the activation of the Nrf2/antioxidant defense pathway in rat palatal tissue, thereby reducing systemic oxidative stress and proinflammatory cytokine levels and promoting healing-associated genes. A circular excisional wound was created in the oral palatal region, and the wound healing process was observed. The rats were divided into two experimental groups in which either hydrogen-rich water or distilled water was consumed. In the drinking hydrogen-rich water, the palatal wound healing process was accelerated compared to that in the control group. As molecular hydrogen upregulated the Nrf2 pathway, systemic oxidative stresses were decreased by the activation of antioxidant activity. Furthermore, hydrogen-rich water intake reduced proinflammatory cytokine levels and promoted the expression of healing-associated factors in rat palatal tissue. In conclusion, hydrogen-rich water intake exhibited multiple beneficial effects through activation of the Nrf2/antioxidant defense pathway. The results of this study support the hypothesis that oral administration of hydrogen-rich water benefits the wound healing process by decreasing oxidative stress and inflammatory responses

就寝時マウスガードを使用することによる、再発性アフタ性口内炎に対する予防効果 : 予備的介入研究

Recurrent aphthous stomatitis (RAS) is the most common inflammatory ulceration in the oral mucosa of otherwise healthy individuals and is often accompanied by severe pain. However, the etiology of RAS is not completely understood, and currently, no therapy can completely prevent RAS recurrence. In our clinical experience, we noticed that patients using a night guard, which is often used for bruxism treatment, did not develop RAS. Therefore, the aim of this study was to determine whether mouthguard use can suppress RAS development. The cohort of this interventional, prospective, single‐center, and self‐controlled study included 20 subjects who developed RAS at least once a month. The oral health of all the subjects was recorded for 60 days before and after intervention with a mouthguard. The average number of RAS incidences decreased from 5.5 to 1.0, the average days until healing decreased from 7.3 to 5.6, and the period with RAS decreased from 31.5 to 5.0 with mouthguard use. Mouthguard use may be beneficial for preventing RAS development

ヒト歯肉線維芽細胞における酸化ストレスに対するレスベラトロール，ケルセチン，及びN-アセチルシステインの生物学的影響

In periodontitis, production of reactive oxygen species (ROS) by neutrophils induces oxidative stress and deteriorates surrounding tissues. Antioxidants reduce damage caused by ROS and are used to treat diseases involving oxidative stress. This study summarizes the different effects of resveratrol, quercetin, and N-acetylcysteine (NAC) on human gingival fibroblasts (HGFs) under oxidative stress induced by hydrogen peroxide. Real-time cytotoxicity analyses reveals that resveratrol and quercetin enhanced cell proliferation even under oxidative stress. Of the antioxidants tested, resveratrol is the most effective at inhibiting ROS production. HGFs incubated with resveratrol and quercetin up-regulate the transcription of type I collagen gene after 3 h, but only resveratrol sustained this up-regulation for 24 h. A measurement of the oxygen consumption rate (OCR, mitochondrial respiration) shows that resveratrol generates the highest maximal respiratory capacity, followed by quercetin and NAC. Simultaneous measurement of OCR and the extracellular acidification rate (non-mitochondrial respiration) reveals that resveratrol and quercetin induce an increase in mitochondrial respiration when compared with untreated cells. NAC treatment consumes less oxygen and enhances more non-mitochondrial respiration. In conclusion, resveratrol is the most effective antioxidant in terms of real-time cytotoxicity analysis, reduction of ROS production, and enhancement of type I collagen synthesis and mitochondrial respiration in HGFs