Deferoxamine-Induced Migration and Odontoblast Differentiation via ROS-Dependent Autophagy in Dental Pulp Stem Cells.

BACKGROUND/AIMS: As a vital degradation and recycling system, autophagy plays an essential role in regulating the differentiation of stem cells. We previously showed that iron chelator deferoxamine (DFO) could promote the repair ability of dental pulp stem cells (DPSCs). Here, we investigated the effect of DFO in autophagy and the role of autophagy in regulating the migration and odontoblast differentiation of DPSCs. METHODS: Transmission electron microscopy, immunofluorescence staining and western blotting were performed to evaluate the autophagic activity of DPSCs. Transmigration assay, alkaline phosphatase staining/activity, alizarin red S staining and quantitative PCR were performed to examine the migration and odontoblast differentiation of DPSCs. Reactive oxygen species (ROS) levels and the effects of ROS scavenger in autophagy induction were also detected. Autophagy inhibitors (3-MA and bafilomycin A1) and lentiviral vectors carrying ATG5 shRNA sequences were used for autophagy inhibition. RESULTS: Early exposure to DFO promoted the mineralization of DPSCs and increased autophagic activity. Autophagy inhibition suppressed DFO-induced DPSC migration and odontoblast differentiation. Furthermore, DFO treatment could induce autophagy partly through hypoxia-inducible factor 1α/B cell lymphoma 2/adenovirus E1B 19K-interacting protein 3 (HIF-1α/BNIP3) pathway in a ROS-dependent manner. CONCLUSION: DFO increased DPSC migration and differentiation, which might be modulated through ROS-induced autophagy.

Trefoil factor 3 peptide regulates migration via a Twist-dependent pathway in gastric cell.

Trefoil factor 3 (TFF3) is a member of the TFF-domain peptide family and essential in regulating cell migration and maintaining mucosal integrity in gastrointestinal tract. However, the role of TFF3 and its downstream regulating mechanisms in cancer cell migration remain unclear. We previously reported that TFF3 prolonged the up-regulation of Twist protein to modulate IL-8 secretion in intestinal epithelial cells. In this study, we investigated the role of Twist protein in TFF3-induced migration of SGC7901 cells. While Twist was activated by TFF3, siRNA-mediated knockdown of Twist abolished TFF3-induced cell migration. Furthermore, the migration related marker CK-8 as well as ZO-1 and MMP-9 was also regulated by TFF3 via a Twist-dependent mechanism. Our study suggests that Twist, as an important potential downstream effector, plays a key role in TFF3-modulated metastasis in gastric cancer and can be a promising therapeutic target against intestinal-type gastric cancer.

Progress risk assessment of oral premalignant lesions with saliva miRNA analysis.

BACKGROUND: Oral cancer develops through multi-stages: from normal to mild (low grade) dysplasia (LGD), moderate dysplasia, and severe (high grade) dysplasia (HGD), to carcinoma in situ (CIS) and finally invasive oral squamous cell carcinomas (OSCC). Clinical and histological assessments are not reliable in predicting which precursor lesions will progress. The aim of this study was to assess the potential of a noninvasive approach to assess progress risk of oral precancerous lesions. METHODS: We first used microRNA microarray to profile progressing LGD oral premaligant lesions (OPLs) from non-progressing LGD OPLs in order to explore the possible microRNAs deregulated in low grade OPLs which later progressed to HGD or OSCC. We then used RT-qPCR to detect miRNA targets from the microarray results in saliva samples of these patients. RESULTS: We identified a specific miRNA signature that is aberrantly expressed in progressing oral LGD leukoplakias. Similar expression patterns were detected in saliva samples from these patients. CONCLUSIONS: These results show promise for using saliva miRNA signature for monitoring of cancer precursor lesions and early detection of disease progression.

Egr-1 promotes cell proliferation and invasion by increasing ß-catenin expression in gastric cancer.

BACKGROUND: Abnormal expression of early growth response gene 1 (Egr-1) and ß-catenin may play a crucial role in the development and progression of human cancer. However, little is known about the expression and underlying molecular mechanisms in which Egr-1 and ß-catenin are involved in the development and progression of gastric cancer. AIMS: The purpose of this study was to elucidate the potential relationship between Egr-1 and ß-catenin expression in gastric cancer, which contributes to finding new molecular carcinogenesis as a potential therapeutic target for gastric cancer. METHODS: In a sample of 102 cases of human gastric cancer, the expression of Egr-1 and ß-catenin was detected using immunohistochemistry. Egr-1 gene was transfected into gastric cancer SGC7901 cells and its role in proliferation and cell invasion was detected by MTT assay, flow cytometry, wound-healing and transwell invasion assay. Western blot analysis was used to study the expression of ß-catenin and cyclin D1 proteins. RESULTS: Upregulated Egr-1 and ß-catenin protein expression were strongly correlated with cancer progression and depth of invasion in gastric cancer. ß-catenin, present mainly in cytoplasmic and nucleus of gastric cancer cells, was also positively correlated with Egr-1 expression in gastric cancer. Furthermore, the overexpression of Egr-1 upregulated ß-catenin expression level, promoted cell proliferation, increased cell population in S-phase and enhanced gastric cancer cell migration and invasion in vitro. CONCLUSIONS: Egr-1 might contribute to gastric cancer proliferation and invasion through activation of the ß-catenin signaling pathway.

Altered salivary microbiota profile in patients with abdominal aortic aneurysm.

Evidence suggests that the DNA of oral pathogens is detectable in the dilated aortic tissue of abdominal aortic aneurysm (AAA), one of the most fatal cardiovascular diseases. However, the association between oral microbial homeostasis and aneurysm formation remains largely unknown. In this study, a cohort of individuals, including 53 AAA patients and 30 control participants (CTL), was recruited for salivary microbiota investigation by 16S rRNA gene sequencing and bioinformatics analysis. Salivary microbial diversity was decreased in AAA compared with CTL, and the microbial structures were significantly separated between the two groups. Additionally, significant taxonomic and functional changes in the salivary microbiota of AAA participants were observed. The genera Streptococcus and Gemella were remarkably enriched, while Selenomonas, Leptotrichia, Lautropia and Corynebacterium were significantly depleted in AAA. Co-occurrence network analysis showed decreased potential interactions among the differentially abundant microbial genera in AAA. A machine-learning model predicted AAA using the combination of 5 genera and 14 differentially enriched functional pathways, which could distinguish AAA from CTL with an area under the receiver-operating curve of 90.3 %. Finally, 16 genera were found to be significantly positively correlated with the morphological parameters of AAA. Our study is the first to show that AAA patients exhibit oral microbial dysbiosis, which has high predictive power for AAA, and the over-representation of specific salivary bacteria may be associated with AAA disease progression. Further studies are needed to better understand the function of putative oral bacteria in the etiopathogenesis of AAA. Importance: Host microbial dysbiosis has recently been linked to AAA as a possible etiology. To our knowledge, studies of the oral microbiota and aneurysms remain scarce, although previous studies have indicated that the DNA of some oral pathogens is detectable in aneurysms by PCR method. We take this field one step further by investigating the oral microbiota composition of AAA patients against control participants via high-throughput sequencing technologies and unveiling the potential microbial biomarker associated with AAA formation. Our study will provide new insights into AAA etiology, treatment and prevention from a microecological perspective and highlight the effects of oral microbiota on vascular health.

Periodontitis exacerbates atherosclerosis through Fusobacterium nucleatum-promoted hepatic glycolysis and lipogenesis.

AIMS: Positive associations between periodontitis (PD) and atherosclerosis have been established, but the causality and mechanisms are not clear. We aimed to explore the causal roles of PD in atherosclerosis and dissect the underlying mechanisms. METHODS AND RESULTS: A mouse model of PD was established by ligation of molars in combination with application of subgingival plaques collected from PD patients and then combined with atherosclerosis model induced by treating atheroprone mice with a high-cholesterol diet (HCD). PD significantly aggravated atherosclerosis in HCD-fed atheroprone mice, including increased en face plaque areas in whole aortas and lesion size at aortic roots. PD also increased circulating levels of triglycerides and cholesterol, hepatic levels of cholesterol, and hepatic expression of rate-limiting enzymes for lipogenesis. Using 16S ribosomal RNA (rRNA) gene sequencing, Fusobacterium nucleatum was identified as the most enriched PD-associated pathobiont that is present in both the oral cavity and livers. Co-culture experiments demonstrated that F. nucleatum directly stimulated lipid biosynthesis in primary mouse hepatocytes. Moreover, oral inoculation of F. nucleatum markedly elevated plasma levels of triglycerides and cholesterol and promoted atherogenesis in HCD-fed ApoE-/- mice. Results of RNA-seq and Seahorse assay indicated that F. nucleatum activated glycolysis, inhibition of which by 2-deoxyglucose in turn suppressed F. nucleatum-induced lipogenesis in hepatocytes. Finally, interrogation of the molecular mechanisms revealed that F. nucleatum-induced glycolysis and lipogenesis by activating PI3K/Akt/mTOR signalling pathway in hepatocytes. CONCLUSIONS: PD exacerbates atherosclerosis and impairs lipid metabolism in mice, which may be mediated by F. nucleatum-promoted glycolysis and lipogenesis through PI3K/Akt/mTOR signalling in hepatocytes. Treatment of PD and specific targeting of F. nucleatum are promising strategies to improve therapeutic effectiveness of hyperlipidaemia and atherosclerosis.

Oral pathogens exacerbate Parkinson's disease by promoting Th1 cell infiltration in mice.

BACKGROUND: Parkinson's disease (PD) is a common chronic neurological disorder with a high risk of disability and no cure. Periodontitis is an infectious bacterial disease occurring in periodontal supporting tissues. Studies have shown that periodontitis is closely related to PD. However, direct evidence of the effect of periodontitis on PD is lacking. Here, we demonstrated that ligature-induced periodontitis with application of subgingival plaque (LIP-SP) exacerbated motor dysfunction, microglial activation, and dopaminergic neuron loss in 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice. RESULTS: The 16S rRNA gene sequencing revealed that LIP-SP induced oral and gut dysbiosis. Particularly, Veillonella parvula (V. parvula) and Streptococcus mutans (S. mutans) from oral ligatures were increased in the fecal samples of MPTP + LIP-SP treated mice. We further demonstrated that V. parvula and S. mutans played crucial roles in LIP-SP mediated exacerbation of motor dysfunction and neurodegeneration in PD mice. V. parvula and S. mutans caused microglial activation in the brain, as well as T helper 1 (Th1) cells infiltration in the brain, cervical lymph nodes, ileum and colon in PD mice. Moreover, we observed a protective effect of IFNγ neutralization on dopaminergic neurons in V. parvula- and S. mutans-treated PD mice. CONCLUSIONS: Our study demonstrates that oral pathogens V. parvula and S. mutans necessitate the existence of periodontitis to exacerbate motor dysfunction and neurodegeneration in MPTP-induced PD mice. The underlying mechanisms include alterations of oral and gut microbiota, along with immune activation in both brain and peripheral regions. Video Abstract.

Characteristics and Correlations of the Oral and Gut Fungal Microbiome with Hypertension.

The mycobiome is an essential constituent of the human microbiome and is associated with various diseases. However, the role of oral and gut fungi in hypertension (HTN) remains largely unexplored. In this study, saliva, subgingival plaques, and feces were collected from 36 participants with HTN and 24 healthy controls for metagenomic sequencing. The obtained sequences were analyzed using the Kraken2 taxonomic annotation pipeline to assess fungal composition and diversity. Correlations between oral and gut fungi and clinic parameters, between fungi within the same sample types, and between different sample types were identified by Spearman's correlation analysis. Overall, the subgingival fungal microbiome had substantially higher alpha diversity than the salivary and fecal fungal microbiomes. The fungal microbiomes of the three sample types displayed distinct beta diversity from each other. Oral fungi but not gut fungi in HTN had beta diversity significantly different from that of controls. Among the fungi shared in the oral cavity and gut, Exophiala was the genus with the most notable changes. Exophiala spinifera was the most abundant salivary species in HTN. Some fungal species directly correlated with blood pressure, including gut Exophiala xenobiotica and Exophiala mesophila. The markedly impaired ecological cocorrelation networks of oral and gut fungi in HTN suggested compromised association among fungal species. Most fungi were shared in the oral cavity and gut, and their correlations suggested the potential interplays between oral and gut fungi. In conclusion, the oral cavity and intestine have unique fungal ecological environments. The fungal enrichment and ecology in HTN, the correlations between oral and gut fungi, and the associations between oral and gut fungi and clinical parameters suggest an important role that the fungal microbiome may play in HTN. IMPORTANCE Our study fills the gap in human studies investigating the oral and gut fungal microbiota in association with blood pressure. It characterizes the diversity and composition of the oral and gut fungal microbiome in human subjects, elucidates the dysbiosis of fungal ecology in a hypertensive population, and establishes oral-gut fungal correlations and fungus-clinical parameter correlations. Targeting fungi in the oral cavity and/or gut may provide novel strategies for the prevention and treatment of hypertension.

Roles of oral microbiota and oral-gut microbial transmission in hypertension.

INTRODUCTION: Considerable evidence has linked periodontitis (PD) to hypertension (HTN), but the nature behind this connection is unclear. Dysbiosis of oral microbiota leading to PD is known to aggravate different systematic diseases, but the alteration of oral microbiota in HTN and their impacts on blood pressure (BP) remains to be discovered. OBJECTIVES: To characterize the alterations of oral and gut microbiota and their roles in HTN. METHODS: We performed a cross-sectional (95 HTN participants and 39 controls) and a 6-month follow-up study (52 HTN participants and 26 controls) to analyze the roles of oral and gut microbiota in HTN. Saliva, subgingival plaques, and feces were collected for 16S rRNA gene sequencing or metagenomic analysis. C57BL/6J mice were pretreated with antibiotics to deplete gut microbiota, and then transplanted with human saliva by gavage to test the impacts of abnormal oral-gut microbial transmission on HTN. RESULTS: BP in participants with PD was higher than no PD in both cross-sectional and follow-up cohort. Relative abundances of 14 salivary genera, 15 subgingival genera and 10 gut genera significantly altered in HTN and those of 7 salivary genera, 12 subgingival genera and 6 gut genera significantly correlated with BP. Sixteen species under 5 genera were identified as oral-gut transmitters, illustrating the presence of oral-gut microbial transmission in HTN. Veillonella was a frequent oral-gut transmitter stably enriched in HTN participants of both cross-sectional and follow-up cohorts. Saliva from HTN participants increased BP in hypertensive mice. Human saliva-derived Veillonella successfully colonized in mouse gut, more abundantly under HTN condition. CONCLUSIONS: PD and oral microbiota are strongly associated with HTN, likely through oral-gut transmission of microbes. Ectopic colonization of saliva-derived Veillonella in the gut may aggravate HTN. Therefore, precise manipulations of oral microbiota and/or oral-gut microbial transmission may be useful strategies for better prevention and treatment of HTN.

Endoplasmic reticulum stress response mediated by the PERK-eIF2α-ATF4 pathway is involved in odontoblastic differentiation of human dental pulp cells.

OBJECTIVE: RNA-activated protein kinase-like ER-resident kinase (PERK) was a major transducer of Endoplasmic reticulum (ER) stress response and it directly phosphorylated α-subunit of eukaryotic initiation factor 2 (eIF2α), which specifically promoted the translation of activating transcription factor 4 (ATF4), an important transcription factor in cells' differentiation. The purpose of this study was to establish whether ER stress mediated by PERK-eIF2α-ATF4 pathway was involved in odontoblastic differentiation of human dental pulp cells (DPCs). METHODS: DPCs were isolated from extracted teeth and cultured in odontogenic medium. A recombinant lentiviral vector was constructed to transfect DPCs for PERK knockdown. Alkaline phosphatase (ALP) and Alizarin red S staining were used to characterize the odontoblastic differentiation. Real-time polymerase chain reactions (RT-PCR) were performed to analyze the genes' expressions in DPCs' odontoblastic differentiation. The mRNA and protein levels of ER stress markers were examined by RT-PCR and western blot. RESULTS: DPCs cultured in odontogenic media showed increased ALP activity and mineralized nodule formation. Notably, treatment with differentiation medium resulted in the up-regulation of genes, such as osteocalcin (OCN), bone sialoprotein (BSP), dentin sialophosphoprotein (DSPP), splicing x-box binding protein-1 (sXBP1), ATF4 and glucose-regulated protein 78 (GRP78). Meanwhile, the expressions of PERK-eIF2α-ATF4 pathway proteins, phosphorylated PERK, phosphorylated eIF2α and ATF4, increased in odontoblastic induction cells compared with controls. Furthermore, inhibition of PERK (PERK knockdown) decreased ALP activity and matrix mineralization in DPCs accompanied by the decrease expression of phosphorylated eIF2α and ATF4. CONCLUSION: These results suggested that PERK-eIF2α-ATF4 pathway was involved in the odontoblastic differentiation of DPCs.

[Chemotherapy resistance induced by interleukin-6 in ovarian cancer cells and its signal transduction pathways].

OBJECTIVE: To study the mechanism of chemotherapy resistance caused by interleukin-6 (IL-6) in ovarian cancer cells and its related signal pathways. METHODS: Ovarian cancer cell lines A2780 (IL-6 receptor positive, while non-IL-6-expressing and cisplatin/paclitaxel-responsive) and SKOV3 cell lines (overexpressing of IL-6 receptor and IL-6 and cisplatin/paclitaxel-resistant) were suitable models for this study. The effect of exogenous (a short period of treatment with recombination IL-6) and endogenous IL-6 (by transfecting with plasmid encoding for sense IL-6) in A2780 cells or deleting of endogenous IL-6 expression in SKOV3 cells (by transfecting with plasmid encoding for antisense IL-6) on the sensitivity to cisplatin and paclitaxel was investigated. Meanwhile, the mechanism of chemotherapy resistance caused by IL-6 in ovarian cancer cells and its related signal pathways were also analyzed. RESULTS: We found that both exogenous and endogenous IL-6 induce cisplatin and paclitaxel resistance in non-IL-6-expressing A2780 cells (the resistance multiple to cisplatin and paclitaxel was: exogenous, 6.25 and 7.31; endogenous, 7.13-8.34 and 7.61-10.70), while deleting of endogenous IL-6 expression in IL-6-overexpressing SKOV3 cells promotes its sensitivity to anticancer drugs (the resistance multiple to cisplatin and paclitaxel was 0.15 and 0.10, 0.10 and 0.08). IL-6 significantly up-regulated the expression levels of mRNA and protein of drug resistance-associated genes, MDR1 and GST-π, and apoptosis-inhibiting genes, bcl-2, bcl-xL and XIAP in a dose-dependent manner in A2780 cells. In accordance with this finding, the mRNA and protein levels of MDR1 and GST-π enhanced in sense IL-6-transfected A2780 cells, and reduced in antisense IL-6-transfected SKOV3 cells compared with the corresponding parental and control vector-transfected cells, which had no difference. It was found that PD98059 [mitogen-activated protein kinase-extracellular signal-regulated kinase (MEK) inhibitor] and wortmannin [phosphatidylinositol 3-kinase (PI3K) inhibitor] significantly antagonized IL-6-induced phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B (Akt), respectively, and both of them blocked IL-6-induced cisplatin and paclitaxel resistance and the inhibitory effects of PD98059 and wortmannin were dependent on its concentration. CONCLUSIONS: These data suggest that IL-6-induced chemoresistance may be associated with increase of both drug resistance-associated genes (MDR1 and GST-π) and apoptosis-inhibiting genes (bcl-2, bcl-xL and XIAP), and activation of MEK/ERK and PI3K/Akt. Therefore, modulation of IL-6 expression or its related signaling pathway may be a promising strategy of treatment for drug-resistant ovarian cancer.

[The risk and prevention of bio-aerosol transmission in dental clinics].

Corona virus disease 2019 (COVID-19) has become a Public Health Emergency of International Concern since its outbreak, and whether COVID-19 can transmit by aerosol remains controversial. The problem of bio-aerosol transmission in the relatively confined dental clinics has aroused wide attention in the field of dentistry. This review provided a most updated summary on the relation between bio-aerosols and dental clinics, which included the microorganisms in bio-aerosols, the bio-aerosol transmission and the sources testing methods, temporal and spatial distribution of dental bio-aerosols and summarized how to reduce the exposure to bio-aerosols in dental clinics.

[Management and prevention of dental emergency during corona virus disease 2019 (COVID-19) epidemic].

The outbreak of corona virus disease 2019 (COVID-19) has developed rapidly and the situation of prevention and control is severe. During the epidemic period of COVID-19, due to the particularity of diagnosis and treatment of oral diseases, there is great challenges for how to deal with various types of dental emergency. In order to prevent and control the epidemic situation strictly, and to perform a scientific and orderly clinical diagnosis and treatment of dental emergency, this article provided suggestions on personnel management training, procedures and treatment, protection and disinfection of dental emergency during COVID-19 epidemic, and reference for dental institutions and medical staff.

[Effect of recombinant connective tissue growth factor on proliferation and odontogenic differentiation of dental pulp cells].

PURPOSE: To analyze the effect of recombinant connective tissue growth factor(rCTGF) on proliferation and differentiation of human dental pulp cells(hDPCs). METHODS: Human dental pulp cells were cultured in vitro and treated with rCTGF at different concentrations (0, 1, 10, 100 ng/mL). The proliferation of dental pulp cells was detected by CCK8 assay. The formation of mineralized nodules was determined by alizarin red staining and half-quantitative alizarin Red S assay. qRT-PCR was utilized to detect the expression of odontogenic differentiation related genes DMP-1, DSPP and OC, and the phosphorylation level of ERK1/2 signaling pathway was detected by Western blot. The data were analyzed with SAS 9.3 software package. RESULTS: High concentration of rCTGF(100 ng/mL) could promote proliferation of dental pulp cells. After mineralization induction, 10 g/mL rCTGF had the best effect on promoting the formation of mineralized nodules in dental pulp cells, and calcium ion deposition was the most obvious(P<0.05). The expression of odontogenic differentiation related genes DMP-1 and DSPP was significantly up-regulated(P<0.05). Western blot results showed that hDPCs stimulated by 10 ng/mL rCTGF could increase the expression of p-ERK1/2. CONCLUSIONS: rCTGF may promote the proliferation and differentiation of human dental pulp cells through activating ERK1/2 signaling pathway.

[Effect of serum starvation and culture to confluence on cell cycle synchronization and mineralization of human dental pulp cells].

PURPOSE: To compare the effect of serum starvation and culture to confluence on cell cycle synchronization and mineralization of human dental pulp cells (hDPCs). METHODS: HDPCs were cultured to 80% and 100% confluence respectively, and then cultured for 24, 48 and 72 hours by culture medium containing 0.5% fetal bovine serum(FBS). Cell cycle of hDPCs were identified by flow cytometry. Then hDPCs cultured by serum starvation for 48h after culturing to 100% confluence were used as the experimental group, and hDPCs cultured to 80% confluence were used as the control group. The expression of alkaline phosphatase(ALP), collagen type Ⅰ(COL-Ⅰ) and osteocalcin(OCN) was detected at gene level; activity of ALPase was detected at protein level. SPSS 13.0 software was used for statistical analysis. RESULTS: When hDPCs were cultured by serum starvation for 48h after culturing to 100% confluence, cells at G0/G1 stage were more than culture to 100% confluence and serum starvation group (P＜0.05). At the genetic level, the expression of COL-Ⅰand OC in the experimental group was not statistically different from that of the control group, but can promote the expression of ALP(P＜0.05), and stimulate the secretion of hDPCs at protein level at the same time (P＜0.05). CONCLUSIONS: Culture to confluence combined serum starvation can synchronize more hDPCs at G0/G1 stage and promote mineralization of hDPCs.

Effect of Lactobacillus acidophilus and Porphyromonas gingivalis on proliferation and apoptosis of gingival epithelial cells.

PURPOSE: This study aimed to evaluate the possible antagonistic effects of Lactobacillus acidophilus on Porphyromonas gingivalis, and detect inhibition of Lactobacillus acidophilus on Porphyromonas gingivalis when they are co-cultured with human gingival epithelial cells. MATERIALS AND METHODS: Human gingival epithelial cells were co-cultured with Lactobacillus acidophilus and Porphyromonas gingivalis alone or together. The amount of Porphyromonas gingivalis adhering to or invading the epithelial cells were determined by bacterial counts. The cellular proliferation was assayed by the MTT method. Apoptosis was detected by flow cytometry with apoptosis detection kit. RESULTS: On one hand, Lactobacillus acidophilus reduced the inhibitory effect of Porphyromonas gingivalis on the human gingival epithelial cells proliferation in a dose dependent manner. On the other hand, Porphyromonas gingivalis induced significant apoptosis on human gingival epithelial cells, and Lactobacillus acidophilus inhibited this apoptosis-inducing effect of Porphyromonas gingivalis in a dose dependent manner. CONCLUSIONS: Porphyromonas gingivalis inhibits the proliferation and induces the apoptosis of human gingival epithelial cells. Lactobacillus acidophilus could attenuate this effect in a dose-dependent manner, and it thus reduces the destruction from pathogens. Lactobacillus acidophilus could be an effective candidate for probiotic therapy in periodontal diseases.

[Establishment of a model of endoplasmic reticulum stress response in dental pulp cells induced by tunicamycin].

PURPOSE: The aim of this study was to establish a model of endoplasmic reticulum (ER) stress in dental pulp cells(DPCs) induced by tunicamycin to better understand the molecular mechanism of DPCs related diseases mediated by ER stress. METHODS: DPCs were cultured using modified tissue explant technique in vitro and cultured in presence or absence of tunicamycin. DPCs' viability was measured by methylthiazol tetrazolium (MTT) assay. The mRNA level of ER stress markers was examined by RT-PCR. The data were analyzed with SPSS17.0 software package. RESULTS: The proliferative ability of DPCs decreased when exposed to tunicamycin in a dose-dependent manner. Treatment with tunicamycin resulted in up-regulation of ER stress genes, such as splicing x-box binding protein-1(sXBP1), activating transcription factor 4(ATF4), glucose-regulated protein 78(GRP78) and C/EBP homologous protein (CHOP). CONCLUSIONS: The results indicate that ER stress response is induced in DPCs by tunicamycin, and the ER stress model is successfully established.

[Effect of pulsed dye laser on inhibiting early scar after maxillofacial trauma].

PURPOSE: The study was designed to explore an effective method to control early scar after maxillofacial trauma and improve the satisfaction of clinical treatment. METHODS: Fifty skin lesions after maxillofacial trauma were divided into the experimental group and control group. Patients in the experimental group were treated with pulsed dye laser when taking out stitches, 15, 30 and 60 days later. Digital microscope photos were taken and lesion area was measured before and 3 months after laser irradiation. Adverse effects were recorded during and after each treatment as well. All patients were asked to rate their satisfaction at 3-month of follow-up. Statistical analysis was performed using SPSS 13.0 software package. RESULTS: The efficiency of the experimental group was 74% and 37 lesions were cured or significantly improved, while the efficiency rate was 22% in the control group. Area reduction of maxillofacial lesions before and after treatment between the two groups was significantly different (P＜0.05). Patients in the experimental group were highly satisfied with the final outcomes. No severe adverse events were observed. CONCLUSIONS: Pulsed dye laser is safe and effective in inhibiting early scar following maxillofacial trauma.

[Elimination of Entercoccus faecalis with different disinfection methods in root canals in vitro].

PURPOSE: To compare the elimination effect against E.faecalis in root canals with different methods. METHODS: Fifty extracted premolars with single root canal were selected. After cleaning and autoclaving, they were contaminated by E.faecalis and incubated for 28 days as models. Then the models were randomly and equally divided into 5 groups and treated as below: specimens in group A were treated with saline irrigation, specimens in group B were treated with 3% NaClO irrigation (as positive control), specimens in group C were treated with PUI, specimens in group D were treated with diode laser radiation, specimens in group E were treated with combination of PUI and diode laser radiation. The specimens from root canals were collected by paper points. The bacterial suspensions were later serially diluted and plated on tryptic soy agar plates to enumerate the CFUs after 48 hours. Statistical analysis was performed using SAS 8.02 software package. RESULTS: As with all parts of the root canal in aggregate, the CFUs of the specimens treated with PUI, diode laser radiation and the combination of them were significantly lower than the specimens treated with saline irrigation (P<0.01), but there was no significant difference among 3 groups (P>0.05). However, the specimens treated with 3% NaClO irrigation had the best effect of disinfection. The number of CFUs in the specimens treated with 3% NaClO was almost zero. There was no significant difference between this group and others in CFUs(P<0.01). CONCLUSIONS: Specimens treated with PUI, diode laser radiation and the combination of them showed great effect of elimination against biofilm of Enterococcus faecalis compared with saline irrigation. Irrigation with 3% NaClO was the most efficient method in this experiment.

[Comparative evaluation of marginal microleakage of three different resins in Class V composite restorations].

PURPOSE: To compare and evaluate microleakage at the occlusal wall and cervical wall in Class V cavities restored with Ivoclar Tetric N Ceram Bulk Fill composite, Tetric N Flow composite and N Ceram nanocomposite. METHODS: Sixty-six extracted human maxillary premolars, which were intact and healthy, were randomly assigned into 3 groups (n=22). Standardized Class V cavities were prepared on the buccal surface of maxillary premolars. The occlusal walls of the cavities were located on the enamel and the cervical walls were located on dentin and cementum. After etching and application of the same bonding agents, the cavities were restored with different composite materials. Group A: Tetric N Ceram nano-hybrid composite , Group B: Tetric N Flow nano-hybrid composite, Group C: Tetric N Ceram Bulk Fill nano-hybrid composite. After curing with soft-start mode, finishing and polishing, the specimens were subjected to thermocycling. The specimens were coated with nail varnish, and immersed in 2% methylene blue solution for 7 days. The teeth were then sectioned longitudinally. Two of the samples chosen randomly from each group were evaluated under scanning electron microscope. Dye penetration of the remaining samples was examined with a stereomicroscope (×40) and scored separately for occlusal and gingival aspect on a 0-3 ordinal scale. The leakage depth was measured with Spot Advanced version 4.6 software package. The data were analyzed with Kruskal-Wallis, Mann-Whitney and Wilcoxon test using SPSS 17.0 software package. RESULTS: Tetric Bulk Fill had significantly less microleakage at the cervical margins than other groups (P<0.05). There was no significant difference at the occlusal margin (P>0.05) between the three groups. There was significant difference between the enamel and cervical wall microleakage (P<0.05). CONCLUSIONS: With the limitations of this study, Tetric Bulk Fill provided the least microleakage at the cervical wall among the three groups. There was no significant difference at the occlusal margin.