Regeneration potential of decellularized periodontal ligament cell sheets combined with 15-deoxy-Δ12,14-prostaglandin J2 nanoparticles in a rat periodontal defect.

Periodontitis is a chronic inflammatory disease characterized by loss of attachment and destruction of the periodontium. Decellularized sheet, as an advanced tissue regeneration engineering biomaterial, has been researched and applied in many fields, but its effects on periodontal regeneration remain unclear. In this study, the biological properties of decellularized human periodontal ligament cell (dHPDLC) sheets were evaluated in vitro. Polycaprolactone/gelatin (PCL/GE) nanofibers were fabricated as a carrier to enhance the mechanical strength of the dHPDLC sheet. 15-deoxy-[Formula: see text]-prostaglandin J2 (15d-PGJ2) nanoparticles were added for anti-inflammation and regeneration improvement. For in vivo analysis, dHPDLC sheets combined with 15d-PGJ2 nanoparticles, with or without PCL/GE, were implanted into rat periodontal defects. The periodontal regeneration effects were identified by microcomputed tomography (micro-CT) and histological staining, and immunohistochemistry. The results revealed that DNA content was reduced by 96.6%. The hepatocyte growth factor, vascular endothelial growth factor, and basic fibroblast growth factor were preserved but reduced. The expressions or distribution of collagen I and fibronectin were similar in dHPDLC and nondecellularized cell sheets. The dHPDLC sheets maintained the intact structure of the extracellular matrix. It could be recellularized by allogeneic human periodontal stem ligament cells and retain osteoinductive potential. Newly formed bone, cementum, and PDL were observed in dHPDLC sheets combined with 15d-PGJ2 groups, with or without PCL/GE nanofibers, for four weeks post-operation in vivo. Bringing together all these points, this new construct of dHPDLC sheets can be a potential candidate for periodontal regeneration in an inflammatory environment of the oral cavity.

Oral Mesenchymal Stem/Progenitor Cells: The Immunomodulatory Masters.

Oral mesenchymal stem/progenitor cells (MSCs) are renowned in the field of tissue engineering/regeneration for their multilineage differentiation potential and easy acquisition. These cells encompass the periodontal ligament stem/progenitor cells (PDLSCs), the dental pulp stem/progenitor cells (DPSCs), the stem/progenitor cells from human exfoliated deciduous teeth (SHED), the gingival mesenchymal stem/progenitor cells (GMSCs), the stem/progenitor cells from the apical papilla (SCAP), the dental follicle stem/progenitor cells (DFSCs), the bone marrow mesenchymal stem/progenitor cells (BM-MSCs) from the alveolar bone proper, and the human periapical cyst-mesenchymal stem cells (hPCy-MSCs). Apart from their remarkable regenerative potential, oral MSCs possess the capacity to interact with an inflammatory microenvironment. Although inflammation might affect the properties of oral MSCs, they could inversely exert a multitude of immunological actions to the local inflammatory microenvironment. The present review discusses the current understanding about the immunomodulatory role of oral MSCs both in periodontitis and systemic diseases, their "double-edged sword" uniqueness in inflammatory regulation, their affection of the immune system, and the underlying mechanisms, involving oral MSC-derived extracellular vesicles.

Effect of 15-Deoxy-Δ12,14-prostaglandin J2Nanocapsules on Inflammation and Bone Regeneration in a Rat Bone Defect Model.

BACKGROUND: 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), one of the major metabolites from prostaglandin D2 in arachidonic acid metabolic pathway, has potential anti-inflammatory properties. The objective of this study was to explore the effects of 15d-PGJ2-loaded poly(D,L-lactide-co-glycolide) nanocapsules (15d-PGJ2-NC) on inflammatory responses and bone regeneration in local bone defect. METHODS: The study was conducted on 96 Wistar rats from June 2014 to March 2016. Saline, unloaded nanoparticles, free 15d-PGJ2or 15d-PGJ2-NC, were delivered through a collagen vehicle inside surgically created transcortical defects in rat femurs. Interleukin-6 (IL-6), interleukin-1 beta (IL-1ß), and tumor necrosis factor-alpha (TNF-α) levels in the surrounding soft tissue were analyzed by Western blot and in the defect by quantitative real-time polymerase chain reaction over 14 days. Simultaneously, bone morphogenetic protein-6 (BMP-6) and platelet-derived growth factor-B (PDGF-B) messenger RNA (mRNA) in the defect were examined. New bone formation and EphrinB2 and osteoprotegerin (OPG) protein expression in the cortical defect were observed by Masson's Trichrome staining and immunohistochemistry over 28 days. Data were analyzed by one-way analysis of variance. Least-significant difference and Dunnett's T3 methods were used with a bilateral P< 0.05. RESULTS: Application of l5d-PGJ2-NC (100 µg/ml) in the local bone defect significantly decreased IL-6, IL-1ß, and TNF-α mRNA and protein, compared with saline-treated controls (P < 0.05). l5d-PGJ2-NC upregulated BMP-6 and PDGF-B mRNA (P < 0.05). New bone formation was observed in the cortical defect in l5d-PGJ2-NC-treated animals from 7th day onward (P < 0.001). Expression of EphrinB2 and OPG presented early on day 3 and persisted through day 28 in 15d-PGJ2-NC group (P < 0.05). CONCLUSION: Stable l5d-PGJ2-NC complexes were prepared that could attenuate IL-6, IL-1ß, and TNF-α expression, while increasing new bone formation and growth factors related to bone regeneration.

Possible socioeconomic and oral hygiene behavioural risk factors for self-reported periodontal diseases in women of childbearing age in a Chinese population.

PURPOSE: To examine the socioeconomic and behavioural risk factors for periodontal disease in women of childbearing age and evaluate the extent of public awareness of the association between oral health and pregnancy in China. MATERIALS AND METHODS: Cross-sectional data from 832 women (including 188 pregnant women) from Yuyao, Zhejiang Province were collected using a structured questionnaire. Demographic data were used to measure the participants' socioeconomic status. The questionnaire assessed knowledge and behaviours related to personal oral hygiene and utilisation of dental care services. Data were divided into pregnant and non-pregnant groups for multivariate logistic regression analysis. RESULTS: In total, 88.3% pregnant women and 74.2% non-pregnant women reported periodontal symptoms. Abnormal body mass index (BMI ≤ 18.5, odds ratio, OR = 0.76, 95% CI 0.27-0.97, P = 0.024; BMI ≥ 23.9, OR = 1.83, 95% CI 1.12-3.35, P = 0.035) was significantly associated with self-reported periodontal disease. Minimal mental stress (OR = 0.56, 95% CI 0.43-0.94, P = 0.028), high annual household income (OR = 0.69, 95% CI 0.17-0.82, P = 0.008), advanced oral hygiene aids (OR = 0.33, 95% CI 0.18-0.49, P < 0.001) and knowledge of the link between pregnancy and periodontal disease (OR = 0.57, 95% CI 0.33-0.96, P = 0.016) were associated with decreased incidence of self reported periodontal disease. CONCLUSIONS: A low socioeconomic background was correlated with the high incidence of self-reported periodontal disease among women of childbearing age in China. Education about primary oral health and equitable distribution of dental services might be expected to improve oral health in this specific population.

Periodontal status and associated risk factors among childbearing age women in Cixi City of China.

OBJECTIVE: To investigate the periodontal status and associated risk factors among women of childbearing age to increase the awareness of oral health. METHODS: The study was conducted on childbearing age women in Cixi, a city in Zhejiang Province in the southeast of China. A total of 754 women participated in periodontal examination while receiving prenatal care. Data of the women were collected from the Cixi Family Planning Commission and during an interview. Clinical periodontal indices, such as bleeding on probing (BOP), probing depth (PD), and clinical attachment level (CAL) were measured during the examination. Statistical analysis on subject-based data was performed. RESULTS: The prevalence of periodontal disease among childbearing age women in Cixi was high (84.7%). A significant association was found between the disease and educational level, pregnancy, taking oral contraceptives, stress, alcohol consumption, overweight, dental visit, and teeth brushing (P<0.05). Women who suffered periodontal disease showed deep PD, obvious BOP, and clinical attachment loss. Among this population, pregnancy was closely associated with higher BOP percentage; teeth brushing no more than once per day or brushing for less than 1 min (P<0.001) after adjusting for age and stress. CONCLUSIONS: The periodontal status of childbearing age women in Cixi needs to be improved urgently. Attention towards the periodontal health should be warranted, especially for those in special statuses and with poor awareness.

Ramsay Hunt syndrome with unilateral polyneuropathy involving cranial nerves V, VII, VIII, and XII in a diabetic patient.

Ramsay Hunt syndrome is a rare complication of the varicella zoster virus, defined as a peripheral facial palsy that typically results from involvement of the facial and auditory nerves. Ramsay Hunt syndrome can be associated with cranial nerves V, VI, IX, and X but rarely with XII. We describe an atypical case of Ramsay Hunt syndrome with multiple cranial nerve involvement of nerves V, VII, VIII, and XII. Antiviral drugs, antibiotics, insulin, and traditional Chinese drugs were administered immediately after admission. After 3 months of combination therapy, the patient had recovered satisfactorily. Herpes zoster can cause severe infections in diabetic patients and should be treated as soon after detection as possible. Ramsay Hunt syndrome should be recognized as a polycranial neuritis characterized by damage to sensory and motor nerves. In addition to facial and vestibular nerve paralysis, Ramsay Hunt syndrome may also involve cranial nerves V and XII.

Inflammatory cytokines, adiponectin, insulin resistance and metabolic control after periodontal intervention in patients with type 2 diabetes and chronic periodontitis.

OBJECTIVE: To evaluate the effects of periodontal intervention on inflammatory cytokines, adiponectin, insulin resistance (IR), and metabolic control and to investigate the relationship between type 2 diabetes mellitus (T2DM) and moderately poor glycemic control and chronic periodontitis. METHODS AND PATIENTS: A total of 190 moderately poorly controlled (HbA1c between 7.5% and 9.5%) T2DM patients with periodontitis were randomly divided into two groups according to whether they underwent periodontal intervention: T2DM-NT and T2DM-T group. The levels of serum adiponectin, C-reactive protein (CRP), tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), lipid profile, glucose, insulin, homeostasis model of assessment-insulin resistance (HOMA-IR) and homeostasis model assessment of ß-cell function (HOMA-ß) were measured at baseline and after 3 months. RESULTS: The levels of clinical periodontal variables, the probing depth, attachment loss, bleeding index, and plaque index were improved significantly in T2DM-T group after 3 months compared to T2DM-NT group (all p<0.01). After 3 months, the serum levels of hsCRP, TNF-α, IL-6, fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), fasting insulin (FINS) and HOMA-IR index decreased, and adiponectin was significantly increased in T2DM-T group compared to those in the T2DM-NT group (p<0.05 or p<0.01). CONCLUSION: Periodontal intervention can improve glycemic control, lipid profile and IR, reduce serum inflammatory cytokine levels and increase serum adiponectin levels in moderately poorly controlled T2DM patients.

Changes of adiponectin and inflammatory cytokines after periodontal intervention in type 2 diabetes patients with periodontitis.

OBJECTIVE: To determine serum adiponectin, C-reactive protein (CRP), TNF-α and IL-6 levels in impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) patients with periodontitis before and after periodontal intervention, and to investigate the relationship between T2DM and periodontitis. METHODS: A total of 50 IGT and 106 T2DM patients with periodontitis were enrolled. The T2DM patients were divided into two groups: T2DM without macrovascular disease (DM1) group and T2DM with macrovascular disease (DM2) group. Each group was randomly divided into two subgroups according to whether they performed periodontal intervention. The normal control group (NC group) consisted of 30 healthy adults. The serum adiponectin, CRP, TNF-α and IL-6 levels were measured at baseline and 3 months after periodontal intervention. RESULTS: The serum adiponectin levels at baseline had decreased tendency with significant difference between each two groups, while CRP, TNF-α, and IL-6 levels had increased tendency with significant difference between each two groups among NC, IGT, DM1 and DM2 groups (all P<0.01). At 3 months after periodontal intervention, the serum adiponectin levels were increased than those without periodontal intervention (all P<0.01), while CRP, IL-6 and TNF-α significantly decreased (all P<0.05) in both IGT and DM1 groups. In DM2 group, only CRP levels at 3 months after periodontal intervention were significantly decreased (P<0.05). Moreover, the HbAlc levels in T2DM patients were improved at 3 months after periodontal invention (P<0.01). CONCLUSION: Periodontal intervention is helpful for glucose control, which may be associated with increased serum adiponectin levels and decreased inflammatory cytokine levels.

[Effect of lipopolysaccharide of Porphyromonas gingivalis on prostaglandin E2 biosynthetic pathway in human monocytic cell strain THP-1].

OBJECTIVE: To investigate the effect of lipopolysaccharide of Porphyromonas gingivalis (Pg-LPS) on the bio-thythetic pathway of prostaglandin E2 (PGE2) and its difference from lipopolysaccharide of Escherichia coli (Ec-LPS). METHODS: Purified Pg-LPS and Ec-LPS were used to stimulate a human monocytic cell strain THP-1. PGE2 concentration was determined by an enzyme immunoassay kit. The release of tritium labeled arachidonic acid (AA) was detected by a liquid scintillation counter. Reverse transcription polymerase chain reaction and western blot were used to analyse the expression of cytosolic phospholipase A2 (cPLA2) enzyme, cyclooxygenase-2 (COX-2), and microsomal prostaglandin E synthase-1 (mPGES-1). RESULTS: The effect of Pg-LPS on induction of PGE2 and release of AA was significantly weaker than that of Ec-LPS (P < 0.05).Increased secretion of PGE2 was observed after stimulation with Pg-LPS for 6 h, which peak at 24 h at (221.40 +/- 29.46) ng/L; or with Ec-LPS for 1-48 h, at (161.80 +/- 17.31) approximately (379.80 +/- 37.35) ng/L. The highest levels of COX-2 and mPGES-1 were shown after 16 h treatment by Pg-LPS, or after 8 h and 16 h by Ec-LPS respectively.cPLA2 inhibitor AACOCF3 could lower the level of LPS-induced release of AA, while it did not influence the production of PGE2. COX-2 inhibitor NS-398 could remarkably reduce the concentration of PGE2. CONCLUSIONS: Pg-LPS showed delayed and weaker effect on PGE2 biosynthetic pathway than Ec-LPS. Pg-LPS-induced PGE2 synthesis was mainly due to enhanced expression of COX-2 and mPGES-1, whereas cPLA2 played an insignificant role.

Infection frequency of Epstein-Barr virus in subgingival samples from patients with different periodontal status and its correlation with clinical parameters.

OBJECTIVE: To detect the infection frequencies of different genotypes of Epstein-Barr virus (EBV) in subgingival samples from chronic periodontitis (CP) patients, and to discuss the correlation between infection with EBV and clinical parameters. METHODS: Nested-PCR assay was used to detect EBV-1 and EBV-2 in subgingival samples from 65 CP patients, 65 gingivitis patients and 24 periodontally healthy individuals. The amplicons were further identified by restriction fragment length polymorphism analysis (RFLP) with endonucleases Afa I and Stu I. Clinical parameters mainly included bleeding on probing (BOP), probing depth (PD), attachment loss (AL) in six sites of the dentition. RESULTS: In CP patients, gingivitis and periodontally healthy individuals, the infection frequencies were 47.7%, 24.6% and 16.7% for EBV-1, and 15.4%, 7.7% and 0% for EBV-2, respectively. In 2 out of the 65 CP patients co-infection of EBV-1 and EBV-2 was found. The positive rate of EBV-1 in chronic periodontitis patients was higher than that in gingivitis patients (P=0.01) and periodontally healthy individuals (P=0.01). But no significant difference was shown in EBV-1 frequency between gingivitis patients and healthy individuals (P>0.05) or in EBV-2 frequency among the three groups (P>0.05). In CP patients, higher mean BOP value was found in EBV-1 or EBV-2 positive patients than that in EBV negative ones (P<0.01), but with no statistical difference in the mean PD or AL value between EBV positive and negative patients (P>0.05). After initial periodontal treatment, 12 out of the 21 EBV-1 positive CP patients did not show detectable EBV-1 in subgingival samples. CONCLUSION: nPCR plus RFLP analysis is a sensitive, specific and stable method to detect EBV-1 and EBV-2 in subgingival samples. Subgingival infection with EBV-1 is closely associated with chronic periodontitis. Infection of EBV in subgingival samples was correlated with BOP.

[Correlation between infection of different glycoprotein B genotypes of human cytomegalovirus and human chronic periodontitis].

OBJECTIVE: To investigate the correlation between infection of different human cytomegalovirus (HCMV) glycoprotein B (gB) genotypes and human chronic periodontitis. METHODS: A nested-polymerase chain reaction (nPCR) was employed to detect HCMV gB gene in the subgingival plaque samples from 65 chronic periodontitis patients and in the gingival crevicular fluid samples from 24 periodontally healthy control. The amplification fragments of gB gene were further genotyped by restriction fragment length polymorphism (RFLP). The correlation among infection with the different HCMV genotypes and the severity of periodontal lesion were evaluated. RESULTS: In terms of teeth examined, the prevalence of HCMV (59.23%, 154/260) in the chronic periodontitis lesions was significantly higher than that of HCMV (32.29%, 31/96) in the periodontally healthy control (P < 0.01). Of the HCMV DNA positive samples from the chronic periodontitis lesions, 11.7% (18/154) was genotyped as gB I, 80.5% (124/154) as gB II, and 7.8% (12/154) as gB I and gB II co-infection, and of the HCMV DNA positive samples from the periodontal healthy control, 45.2% (14/31) was genotyped as gB I, 38.7% (12/31) as gB II, and 16.1% (5/31) as gB I and gB II co-infection. The gB II genotype was more dominant among the chronic periodontitis lesions compared with that among the periodontally healthy control (P < 0.01). In chronic periodontitis, no statistical significance could be found between infection of different HCMV gB genotypes and the different clinical parameters of CAL, PD and GI (P > 0.05). CONCLUSIONS: Subgingival infection with HCMV is closely associated with chronic periodontitis. Infection of HCMV may not correlate directly with severity of periodontitis. However, gB II may be the dominant genotype of HCMV, which is associated with the chronic periodontitis.

Effects of IGF-II on promoting proliferation and regulating nitric oxide synthase gene expression in mouse osteoblast-like cell.

OBJECTIVE: To investigate the effects of insulin-like growth factor II (IGF-II) on promoting cell proliferation, regulating levels of cellular nitric oxide (NO) and mRNA transcriptions of inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) in mouse osteoblast-like cells. METHODS: Mouse osteoblastic cell line MC3T3-E1 was selected as the effective cell of IGF-II. After the cells were treated with IGF-II at different concentrations for different time duration, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay was used to examine cell proliferation, and nitrate reductase method was applied to detect NO concentrations in cell culture supernatants and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to determine transcription levels of cellular iNOS and eNOS mRNAs. RESULTS: After the MC3T3-E1 cells were treated with IGF-II at concentration of 1 ng/ml for 72 h, 10 and 100 ng/ml for 24, 48 and 72 h respectively, all the MTT values increased (P<0.05 or P<0.01) with obvious dosage-time dependent pattern. NO levels of the MC3T3-E1 cells treated with 100 ng/ml IGF-II for 48 h, and with 1, 10 and 100 ng/ml IGF-II for 72 h were remarkably lower than that of the normal control, respectively (P<0.05 or P<0.01). After the cells were treated with 100 ng/ml IGF-II for 48 h cellular iNOS mRNA levels were significantly decreased (P<0.01). But the levels of eNOS mRNA in the cells treated with each of the used IGF-II dosages for different time duration did not show any differences compared with the normal control (P>0.05). CONCLUSION: IGF-II at different concentrations could promote proliferation of mouse MC3T3-E1 cell. This cell proliferation promotion was associated with the low NO levels maintained by IGF-II. Higher concentration of IGF-II could down-regulate iNOS gene expression at the level of transcription but not affect transcription of eNOS mRNA, which might be one of the mechanisms for IGF-II maintenance of the low NO levels in MC3T3-E1 cells.

Association between coinfection of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Treponema denticola and periodontal tissue destruction in chronic periodontitis.

BACKGROUND: The association between the infection of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Treponema denticola in chronic periodontitis (CP) and the severity of periodontal disease remains to be elucidated. The aim of this study was to investigate the subgingival infection frequencies of three periodontopathic bacteria in Chinese CP patients and to evaluate the correlations between infection by these bacteria and periodontal destruction. METHODS: A multiple PCR assay using primers derived from 16SrDNA genes of P. gingivalis, A. actinomycetemcomitans and T. denticola was established to measure simultaneously the presence of the three microbes in 162 subgingival samples from 81 Chinese CP patients. RESULTS: The positive rates of P. gingivalis, A. actinomycetemcomitans and T. denticola in the subgingival samples were 84.6%, 83.3% and 88.3%, respectively. Of the subgingival samples, 68% revealed the coinfection of all the three microbes. The infection rates with P. gingivalis, A. actinomycetemcomitans or T. denticola alone was 5.9% (1/17), 17.6% (3/17) and 76.5% (13/17), respectively. A close association was present between the A. actinomycetemcomitans infection and gingival index (GI) (P < 0.01), but not between P. gingivalis or T. denticola infection and GI (P > 0.05). P. gingivalis and A. actinomycetemcomitans were more frequently detectable in middle and deep pockets than in shallow ones (P < 0.01), while T. denticola was found remarkably often in deep pockets (P < 0.05). The coinfection rate of the three microbes was significantly higher in sites with severe periodontitis than in those with mild periodontitis (P < 0.01). CONCLUSIONS: The multiple PCR established in this study can be used as a sensitive and specific method to simultaneously detect all three microbes in subgingival samples. A. actinomycetemcomitans infection may be associated with CP and play an important role in the periodontal tissue destruction. The coinfection of P. gingivalis, A. actinomycetemcomitans and T. denticola can cause more serious periodontal destruction than infection of any one or two of the three microbes.

[Infection frequency of Epstein-Barr virus in subgingival samples from patients with different periodontal status and its correlation with severity of periodontal lesion].

OBJECTIVE: To detect the infection frequencies of different Epstein-Barr virus (EBV) genotypes in subgingival samples of chronic periodontitis, and the correlation among infection with different genotypes and the severity of periodontal lesion. METHODS: Nested PCR (nPCR) with EBV-1 or EBV-2 specific primers was used to detect EBV-1 and EBV-2 in the subgingival samples from 65 chronic periodontitis patients, 65 gingivitis patients and 24 periodontal healthy individuals. The amplicons were further identified by RFLP with endonucleases Afa I and Stu I. By using periodontal attachment loss (AL) and gingival index (GI) as the observing in, the correlation of infection with different EBV genotypes and the severity of periodontal lesion were analyzed. RESULTS: 0.01 ng of EBV-1 DNA could be detectable by the established nPCR. All the samples showed the same detection results by two separated nPCR. All the EBV-1 amplification products (497 bp) by using endonuclease Afa I digestion could be divided into two fragments with 355 bp and 142 bp respectively. After endonuclease Stu I digestion, all the EBV-2 amplification products (165 bp) displayed two fragments with 118 bp and 47 bp respectively. In the samples of chronic periodontitis patients, gingivitis patients, and healthy periodontal tissues, the positive rates were 28.5% (74/260), 16.9% (44/260), and 14.6% (14/96) for EBV-1; and were 8.1% (21/260), 3.1% (8/260), and 0% for EBV-2 respectively, and the total EBV positive rates were 36.5% (95/260), 20.0% (52/260) and 14.6% (14/96) respectively. None of the positive samples was detectable for both the EBV-1 and EBV-2. The positive rates of EBV-1, EBV-2 and the total EBV positive rates in the chronic periodontitis samples were all higher than those in the gingivitis samples (all P < 0.05) and healthy periodontal tissue samples (all P < 0.01), without a significant difference between the gingivitis samples and healthy periodontal tissue samples (P > 0.05). Infection of EBV or EBV-1 or EBV-2 in CP patients could not be associated with AL or GI. CONCLUSION: Subgingival infection with either EBV-1 or EBV-2 is closely associated with chronic periodontitis. Infection of EBV may not correlate directly with severity of periodontitis.

[Effects of insulin-like growth factor II on regulating nitric oxide synthase gene expression in mouse osteoblast-like MC3T3-E1 cells].

OBJECTIVE: To study the effects of insulin-like growth factor II (IGF-II) on regulating the levels of nitric oxide (NO) and the mRNA transcriptions of inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) in mouse osteoblast-like cells. METHODS: Mouse osteoblastic cell line MC3T3-E1 was selected as the effective cell of IGF-II. After the cells were treated with IGF-II at different concentrations for different intervals of time, MTT colorimetry was used for examining the cell proliferation. Nitrate reductase method was applied for detecting the NO concentrations in cell culture supernatants and RT-PCR employed for determining the levels of cellular iNOS and eNOS mRNAs. RESULTS: After the MC3T3-E1 cells were treated with IGF-II at the dosages of 1 microg/L for 72 h, 10 and 100 microg/L for 24, 48 and 72 h respectively, all the MTT values increased markedly (P < 0.05 or P < 0.01). After the cells were treated for 48 and 72 h at the dosage of 100 microg/L IGF-II respectively, the levels of NO in the supernatants of cell cultures and cellular iNOS mRNA decreased significantly (P < 0.01). However, the levels of eNOS mRNA in the cells treated with any of the IGF-II dosages for the different times were stable (P > 0.05). CONCLUSIONS: IGF-II at the dosages of 1 approximately 100 microg/L showed the effects on promoting proliferation, which as probably due to the maintenance of low NO levels. Inducible NOS gene expression at the level of transcription was down regulated in the MC3T3-E1 cell treated with higher dosage of IGF-II (100 microg/L) but eNOS mRNA was not, which might be one of the mechanisms for the maintenance of low NO levels.

[Cloning and expression of Porphyromonas gingivalis pgmA gene encoding outer membrane protein associated with fimbria].

OBJECTIVE: To clone pgmA gene of Porphyromonas gingivalis, to construct the expression vector of the gene and to identify immunity of the fusion protein. METHODS: The pgmA genes from ATCC 33277 and 47A-1 strains of P.gingivalis were amplified by high fidelity PCR. The nucleotide of the target DNA amplification fragments were sequenced after T-A cloning. The pET32a expression vectors inserted with pgmA gene fragments were constructed. PgmA fusion protein was expressed in E.coli strain BL21DE3 induced by IPTG with different dosages. Western blot test by using rabbit antiserum against the fusion protein was applied to determine immunity of the fusion protein. ELISA was applied to determine the immunoreaction of antibody against PgmA fusion protein and 65 strains of P.gingivalis isolates. RESULT: The nucleotide sequence homology of the cloned pgmA gene fragments from ATCC 33277 and 47A-1 strains was 100%. In comparison with the reported corresponding sequences, the homologies of the nucleotide sequences of the cloned pgmA gene fragments were 98.98%, while the homologies of their putative amino acid sequences were 99.18%. The expression output of PgmA fusion protein in pET32a-pgmA-BL21DE3 system was approximately 50% of the total bacterial proteins. PgmA fusion protein was able to induce rabbit to produce specific antibody that could combine with PgmA protein. 92.3% of P. gingivalis isolates (60/65) were able to react with the antibody against PgmA fusion protein. CONCLUSION: An expression system of P.gingivalis pgmA gene with high efficiency was established successfully. The expressed PgmA fusion protein possesse satisfied immunogenicity and immunoreactivity,which can be used as a candidate antigen in detection of P.gingivalis and possible development of corresponding vaccine.