Effects of rhBMP-2/7 Heterodimer and RADA16 Hydrogel Scaffold on Bone Formation During Rabbit Mandibular Distraction.

PURPOSE: The effects of a recombinant human bone morphogenetic protein-2/7 (rhBMP-2/7) heterodimer and a RADA16 (Ac-RADARADARADARADA-CONH2) hydrogel scaffold on bone formation during distraction osteogenesis were evaluated. MATERIALS AND METHODS: Forty New Zealand white rabbits, which underwent mandibular lengthening, were randomly divided into 5 groups. One group served as the control group. The others received 2 µg of rhBMP-2 homodimer, 2 µg of rhBMP-2/7 heterodimer, 100 µL of RADA16, or 100 µL of RADA16 plus 2 µg of rhBMP-2/7 heterodimer in the mandibular distraction gap at the beginning of distraction. Fluorine-18-labeled fluoride positron emission tomography was used to assess osteogenesis both after distraction and at the end of consolidation. Dual-energy x-ray absorptiometry (DEXA) examination and bone histologic findings were also evaluated. RESULTS: At the end of distraction, the radioactivity concentration in the distracted area was significantly greater in the RADA16 plus rhBMP-2/7 heterodimer group than in the other groups (P < .01). The differences among the other 4 groups were also statistically significant in the following order: rhBMP-2/7 heterodimer group greater than the rhBMP-2 homodimer group, which was greater than the RADA16 group (or control group; P < .05). However, the radioactivity concentration of the RADA16 group was slightly greater than that of the control group with a nonsignificant difference (P > .05). By the end of consolidation, the activity in the control group, RADA16 group, rhBMP-2 homodimer group, and rhBMP-2/7 heterodimer group had significantly diminished (P < .05). However, the activity in the RADA16 plus rhBMP-2/7 heterodimer group remained at the same level (P > .05). The DEXA results and bone histologic findings indicated that more callus regeneration was noted in the RADA16 plus rhBMP-2/7 heterodimer group than in any other group. CONCLUSIONS: The use of rhBMP-2/7 heterodimer and RADA16 hydrogel scaffold significantly promoted mandibular distraction osteogenesis.

Effect of heat treatment on H2O2/HCl etched pure titanium dental implant: an in vitro study.

BACKGROUND: Surface chemistry of dental implant plays an important role in osseointegration. Heat treatment might alter surface chemistry and result in different biological response. The aim of this study was to investigate the roles of heat treatment of H2O2/HCl-treated Ti implants in cell attachment, proliferation and osteoblastic differentiation. MATERIAL/METHODS: Sandblasted, dual acid-etched and H2O2/HCl heat-treated discs were set as the control group and sandblasted, dual acid-etched H2O2/HCl-treated discs were the test group. Both groups' discs were sent for surface characterization. MC3T3-E1 cells were seeded on these 2 groups' discs for 3 hours to 14 days, and then cell attachment, cell proliferation and cell differentiation were evaluated. RESULTS: Scanning electron microscope analysis revealed that the titanium discs in the 2 groups shared the same surface topography, while x-ray diffraction examination showed an anatase layer in the control group and titanium hydride diffractions in the test group. The cell attachment of the test group was equivalent to that of the control group. Cell proliferation was slightly stimulated at all time points in the control group, but the alkaline phosphatase (ALP) activity and osteocalcin (OC) production increased significantly in the test group compared with those in the control group at every time point investigated (p<0.05 or p<0.01). Moreover, the osteoblastic differentiation-related genes AKP-2, osteopontin (OPN) and OC were greatly up-regulated in the test group (p<0.05 or p<0.01). CONCLUSIONS: The results implied that surface chemistry played an important role in cell response, and H2O2/HCl etched titanium surface without subsequent heat treatment might improve osseointegration response.

Designer self-assembling peptide scaffold stimulates pre-osteoblast attachment, spreading and proliferation.

A new peptide scaffold was made by mixing pure RADA16 (Ac-RADARADARADARADA-CONH2) and designer peptide RGDA16 (Ac-RADARGDARADARGDA-CONH2) solutions, and investigate any effect on attachment, spreading and proliferation of pre-osteoblast (MC3T3-E1). The peptides, RADA16 and RGDA16, were custom-synthesized. They were solubilized in deionized water at a concentration of 10 mg/ml (1% w/v), the RGDA16 peptide solution was mixed 1:1 with RADA16 solution and a new peptide solution RGDAmix was produced. The RGDAmix and RADA16 solution were directly loaded in 96-well plates and cover slips, and two different peptide scaffolds were formed with the addition of maintenance medium (alpha-MEM) in several minutes. About 1.0 x 10(4) MC3T3-E1 cells were seeded on each hydrogel scaffold, and then the cell morphological changes were observed using a fluorescence microscope at 1 h, 3 h and 24 h timepoint, respectively. Cell attachment was evaluated 1 h, 3 h and 24 h after cell seeding and cell proliferation was determined 4d, 7d and 14d after cell seeding. The RGDAmix scaffold significantly promoted the initial cell attachment compared with the RADA16 scaffold. MC3T3-E1 cells adhered and spread well on both scaffolds, however, cells spread better on the RGDAmix scaffold than on the RADA16 scaffold. Cell proliferation was greatly stimulated when cultured on RGDAmix scaffold. The RGD sequence contained peptide scaffold RGDAmix significantly enhances MC3T3-E1 cells attachment, spreading and proliferation.

Exosomal miR-7 Mediates Bystander Autophagy in Lung after Focal Brain Irradiation in Mice.

This study investigated whether exosomal microRNA-7 (miR-7) mediates lung bystander autophagy after focal brain irradiation in mice. After 10 Gy or sham irradiation of mice brains, lung tissues were extracted for the detection of autophagy markers by immunohistochemistry, western blotting, and quantitative real-time reverse transcription PCR (qRT-PCR), meanwhile the brains were dissociated, the neuron/astrocyte/microglia/oligodendrocyte were isolated, and the miR-7 expression in each population were detected, respectively. A dual-luciferase reporter assay was developed to identify whether Bcl-2 is a target gene of miR-7. After 10 Gy or sham irradiation of astrocytes, exosomes were extracted, stained with Dil (1,1'-Dioctadecyl-3,3,3',3'-Tetramethylindocarbocyanine Perchlorate), and added into non-irradiated astrocytes. Meanwhile, Dil-stained exosomes released from 10 Gy or sham irradiated astrocytes were injected into LC3B-GFP mice via the tail vein. Lung tissues were then extracted for western blotting and qRT-PCR. Irradiation of mouse brains increased the LC3B-II/I ratio, Beclin-1 and miR-7 levels, while decreased the Bcl-2 level in non-irradiated lung tissue. Interestingly, brain irradiation remarkably increased the miR-7 expression in astrocyte and oligodendrocyte. MiR-7 significantly inhibited the luciferase activity of the wild-type Bcl-2-3'-untranslated regions (UTR) reporter vector, but not that of the Bcl-2-3'-UTR mutant vector, indicating that Bcl-2 is directly targeted by miR-7. In in vitro study, the addition of irradiated astrocyte-secreted exosomes increased the LC3B-II/I ratio, Beclin-1 and miR-7 levels, while decreased the Bcl-2 level in non-irradiated astrocytes. Further, the injection of irradiated astrocyte-secreted exosomes through the tail vein increased the lung LC3B-II/I ratio, Beclin-1 and miR-7 level, but decreased the Bcl-2 level in vivo. We concluded that exosomal miR-7 targets Bcl-2 to mediate distant bystander autophagy in the lungs after brain irradiation.

The optimal dose of recombinant human osteogenic protein-1 enhances differentiation of mouse osteoblast-like cells: an in vitro study.

OBJECTIVE: There is no certain conclusion on the effect of recombinant human Osteogenic Protein-1 (OP-1, BMP-7) on the proliferation of the osteoblast-like cell line, MC3T3-E1. Furthermore, the optimal dose of rhOP-1 on cell differentiation still needs to be elucidated. This investigation aims to delineate the biofunctional characteristics of rhOP-1 in inducing osteoblastogenesis of MC3T3-E1 through in vitro time-course and dose-response studies. DESIGN: MC3T3-E1 cells were cultured for 1, 4, 7 days with the addition of different rhOP-1 concentrations (0, 10, 20, 50, 100, 200, 400 ng/ml), and cell proliferation and cell differentiation were examined. RESULTS: MC3T3-E1 cell proliferation was stimulated by rhOP-1 in a dose-dependent manner (0-400 ng/ml) on day 1, whereas on day 4 and 7, it was still stimulated at low concentrations (10, 20, 50 ng/ml) but inhibited at high ones (200, 400 ng/ml). The alkaline phosphatase (ALP) activity, osteocalcin (OC) production, collagen deposition and extracellular matrix mineralization were dramatically elevated by rhOP-1 treatment, as a function of culture time and rhOP-1 concentration, and all of them reached a plateau at the concentration of 200 ng/ml. Real-time quantitative RT-PCR results showed Runx2, AKP-2, OC and Nog mRNA expressions increased in a dose- and time-dependent manner, and their expressions were significantly higher at high rhOP-1 concentrations than that of low ones. No significant differences were found between the effects of 200 ng/ml rhOP-1 and 400 ng/ml rhOP-1 on the differentiation of MC3T3-E1 cells, except the expression of Nog mRNA, whose expression level was much higher at 400 ng/ml than that at 200 ng/ml. CONCLUSIONS: These results suggest that cell proliferation of MC3T3-E1 is depended on culture time and rhOP-1 concentration, rhOP-1 could stimulate the differentiation of MC3T3-E1 cells and the optimal concentration could be 200 ng/ml.

Enhanced attachment, proliferation, and differentiation of human gingival fibroblasts on titanium surface modified with biomolecules.

Surface modification of dental implants with biomolecules is of particularly interest recently. To mimic the structure and function of native extracellular matrix (ECM), a derivative of hyaluronic acid (HA), HA-GRGDSP, was synthesized, Arg-Gly-Asp (RGD)-containing collagen (Col)/HA multilayer polyelectrolyte films (MPFs) coating was fabricated on titanium (Ti) through alternate deposition of Col and HA-GRGDSP with 4.5 assembly cycles; moreover, bioactive molecule, basic fibroblast growth factor (bFGF), was also incorporated into such coating. This coating was then carefully characterized using scanning electronic microscope (SEM) and scanning force microscopy (SFM); bFGF release from the coating was also evaluated. (Col + bFGF)/HA-RGD coating was successfully deposited on Ti surface, and about 300 pg of bFGF could be slowly released from this coating for a week. This coating significantly promoted the initial cell attachment of human gingival fibroblasts (HGFs) compared with other groups (p < 0.05), and HGFs adhered and spread better on this coating than other groups (p < 0.05). Regarding cell proliferation and differentiation of HGFs, they were greatly stimulated when cultured on this coating (p < 0.05). These results indicated that surface modification of Ti using biomolecules might improve the sealing between the neck section of a dental implant and the soft tissue.

[Inhibitive effect of exogenous carbon monoxide-releasing molecules 2 on the activation of Janus kinase/signal transducer and activator of transcription pathway in sepsis].

OBJECTIVE: To study the inhibitive effect of exogenous carbon monoxide-releasing molecules 2 (CORM-2) on the activation of Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway in sepsis. METHODS: RAW264.7 cells were divided into normal control group, LPS group (10 mg/mL LPS, the same concentration below), LPS + inactive CORM-2 (iCORM-2) group, LPS + 50 mmol/L CORM-2 group, and LPS + 100 mmol/L CORM-2 group. TNF-alpha level in the supernatant was determined with ELISA, and the phosphorylation levels of JAK1 and JAK3 were determined with Western blot. Thirty-five male BALB/c mice were divided into normal control group, cecal ligation and puncture (CLP) group, CLP + iCORM-2 (8.0 mg/kg) group and CLP + CORM-2 group (8.0 mg/kg) according to the random number table. Mice in CLP + CORM-2 group were treated the same as mice in CLP group except for administration of CORM-2 after CLP. The plasma levels of TNF-alpha, IL-1beta, and the phosphorylation levels of JAK1, JAK3 in liver tissue were determined with ELISA 24 hours post CLP. Data were processed with t test. RESULTS: Compared with that of normal control group [(1.9 +/- 0.3) pg/mL], the TNF-alpha level [(8.2 +/- 2.7) pg/mL, t = 2.844, P < 0.01] and phosphorylation levels of JAK1, JAK3 in LPS group increased significantly; while TNF-alpha levels in LPS + 50 mmol/L CORM-2 and LPS + 100 mmol/L CORM-2 groups decreased obviously as compared with that of LPS group [(5.7 +/- 1.4), (3.2 +/- 0.9) pg/mL, with t value respectively 2.104 and 2.363, P values all below 0.05], and it was the same with phosphorylation levels of JAK1, JAK3 in a dose-dependent manner. Compared with those of normal control group, plasma levels of TNF-alpha and IL-1beta and phosphorylation levels of JAK1, JAK3 in liver tissue significantly increased in CLP group (with t value respectively 2.916 and 2.796, and P values all below 0.05); while plasma levels of TNF-alpha and IL-1beta and the phosphorylation levels of JAK1, JAK3 in liver tissue decreased significantly in CLP + CORM-2 group (with t value respectively 2.115 and 2.398, and P values all below 0.05). CONCLUSIONS: Exogenous CORM-2 can obviously inhibit the phosphorylation of JAKs molecules and then inhibit the activation of JAK/STAT signal pathway in sepsis, and decrease the expression of downstream cytokines to effectively prevent cascade reaction in the inflammatory response after severe infection.

H2O2/HCl and heat-treated Ti-6Al-4V stimulates pre-osteoblast proliferation and differentiation.

The purpose of the present study was to evaluate the bioactivity of chemical treatment of titanium alloy (Ti-6Al-4V) in vitro. Smooth-surface discs of Ti-6Al-4V were used in this study. Sandblasted, dual acid-etched and H(2)O(2)/HCl heat-treated discs were set as test group, and sandblasted, dual acid-etched discs as control group. SEM and XRD analysis revealed a porous anatase gel layer on rough surface in the test group and a rough surface in the control group. Mouse pre-osteoblasts (MC3T3-E1 cells) were cultured on these 2 group discs, and then cell proliferation and differentiation were examined 4 days, 7 days, and 14 days after cell seeding. Cell proliferation was greatly stimulated at all time points when cultured in test group (P < .05). The alkaline phosphatase (ALP) activity and osteocalcin (OC) production were much higher in the test group compared with the control group at every time point investigated (P < .05). Furthermore, in the test group, the expressions of alkaline phosphatase-2, osteocalcin, and collagen type I alpha 1 mRNAs were significantly up-regulated as compared with those in the control group (P < .05 or P < .01). The results suggested that H(2)O(2)/HCl and heat-treatment might facilitate better integration of Ti-6Al-4V implants with bone.

[Inhibitive effect of exogenous carbon monoxide-releasing molecules 2 on tissue factor expression in sepsis].

OBJECTIVE: To explore the inhibitive effects of exogenous carbon monoxide-releasing molecules 2 (CORM-2) on expression of tissue factor (TF) in sepsis. METHODS: Human umbilical vein endothelial cells (HUVEC) were cultured with trypsin digestion method, which were divided into NC group (with normal treatment), LPS group (with culture of 10 microg/mL LPS), LD group (with 10 microg/mL LPS and DMSO in co-culture), LC1 group (with 10 microg/mL LPS and 10 micromol/L CORM-2 in co-culture), LC2 group (with 10 microg/mL LPS and 50 micromol/L CORM-2 in co-culture), LC3 group (with 10 microg/mL LPS and 100 micromol/L CORM-2 in co-culture). After culture for 4 hours, TF activity, TF protein expression, nuclear factor-kappaB (NF-kappaB) activity were examined. Forty-five C57 BL/6 male mice were randomly divided into NC (without treatment, n = 5), CLP (n = 5) and CLP + CORM-2 (with treatment of 8 mg/kg CROM-2 after CLP, n = 5) groups. The serum samples in CLP, CLP + CORM-2 groups were collected at 2, 6, 12 and 24 post operation hour ( POH, 5 mice at each time point) for determination of TF and TFPI levels,which were also examined in NC group. RESULTS: Compared with those of NC group, TF activity increased (P < 0.01) , TF protein expression and NF-KB activity also increased in LPS group. Compared with those of LPS group, above indices were decreased in LC1, LC2, LC3 groups. The serum level of TF in CLP group at 6 POH was higher than that of NC group (80.0 +/- 11.9 pg/mL vs 58.4 +/- 6.9 pg/mL, P < 0.05), peaked at 12 POH, and still higher than that of NC group at 24 POH, while the serum level of TFPI showed no obvious difference in NC and CLP groups. Compared with that of NC group, TFPI levels obviously increased in CLP + CORM-2 group at 6, 12 POH (23.7 +/-3.5 ng/mL, 24.4 +/- 5.0 ng/mL vs 12.4 +/- 2.8 ng/mL, P < 0.05). CONCLUSIONS: Exogenous CORM can obviously inhibit TF and NF-KB activity,decrease TF protein expression. Meanwhile, it can also decrease serum level of TF, and increase serum level of TFPI, preventing activation of procoagulant system, balancing procoagulant and anticoagulant system in sepsis.

[Clinical evaluation of wedge-shaped defect restored by gingival retraction technique].

OBJECTIVE: To evaluate the periodontal conditions after the wedge-shaped defect was restored by gingival retraction technique. METHODS: A total of 138 mandibular premolars with wedge-shaped defect were selected and divided into A, B groups. Group A was restored with Dyract after using retraction cord. Group B was directly restored with Dyract. Clinical parameters including plaque index (PLI), gingival index (GI), sulcus bleeding index (SBI), probing depth (PD), volumes of gingival crevicular fluid (GCF) and levels of aspartate aminotransferases (AST) of gingival crevicular fluid were measured at baseline, 1 week, 1 month, 3 months and 6 months after operation. RESULTS: There was no difference in PLI, GI, SBI, PD between group A and B during 6 months after operation, while the difference of GCF and AST was significant between group A and B at 3 months and 6 months after operation (P < 0.05, P < 0.01). CONCLUSIONS: Gingival retraction technique applied in wedge-shaped defect restoration can reduce the damage to the periodontal tissue.

[Psychological comparison of patients with soft tissue injuries in oral and maxillofacial region by different kinds of suturing].

OBJECTIVE: To evaluate the psychological situations of patients with soft tissue injuries in oral and maxillofacial region by different kinds of suturing. METHODS: A total of 200 patients were selected and randomly divided into two groups. Group A received intradermic suture while group B underwent para-position suture. All patients were evaluated by hospital anxiety and depression (HAD) scales pre-suture, after one week, one month and three months. RESULTS: The HAD total scores of group B were significantly high compared with group A (P < 0.05) after one week and one month, while there was no difference between group A and group B pre-suture and three months later. CONCLUSIONS: Intradermic suture results in less psychological influence in patients with soft tissue injuries in oral and maxillofacial region.