OBJECTIVETo explore the differentially expressed genes and related signaling pathways in MC3T3-E1 osteo- blasts in response to suitable fluid shear stress values and action time with cDNA microarrays.

METHODSMC3T3-E1 cells cultured on a cover slip were subjected to fluid shear stress using a parallel plate flow chamber. The harvested RNA was used for microarray hybridization comprising approximately 44 170 genes, as well as for the subsequent real-time quantitative polymerase chain reaction validation of expression levels for selected genes. Microarray results were analyzed by using both GO and Pathway analysis.

RESULTSMicroarray analysis indicated that 884 differentially expressed genes were found. Among these genes, 444 were upregulated, whereas 440 were downregulated. The Notch signal and RIG- I -like receptor signaling pathways were involved in the Pathway analysis. GO analysis mainly involved different functional classifications, such as prostaglandin biosynthesis, nitric oxide-mediated signal transduction, calcium mediated signal, and cellular immune response, among others.

CONCLUSIONThe mechanism underlying the protective effect of fluid shear stress on MC3T3-E1 cells might be related to promoting cell survival- and inhibiting cell apoptosis-related signaling pathways and biological processes.

Apoptosis ; Calcium ; Humans ; Oligonucleotide Array Sequence Analysis ; Osteoblasts ; Signal Transduction ; Stress, Mechanical

Mechanical stress plays an important role in bone growth and bone remodeling. It causes stretch stress and fluid shear stress (FSS), which can be sensed by mechanosensory cells, e.g. osteocytes and osteoblasts, and further induce changes of gene expression in those cells. The FSS is thought to be the main cause in this process. However, up to now, it is still not clear what signals are triggered in the mechanosensory cells cultured in vitro and how the FSS exactly affects the expression of specific proteins. Evidences have shown that Ca2+ signaling pathway, Cyclooxygenase-prostaglandin E2 pathway, protein kinase A/protein kinase C (PKA/PKC) pathway, and drosophila mothers against decapentaplegic (Smad) protein pathway may be the key players in osteoblast differentiation by FSS. The precise mechanism involved in mechanotransduction and signal transduction remains to be elucidated. The present review gives a brief summary on the effects of these signaling pathways on the differentiation of osteoblasts cultured in vitro under FSS, to get the message of the present situation of the research on the stress transmission and signal transduction influencing osteoblast molecular activity, and to provide reference for further study on its specific mechanism.
Animals ; Calcium Signaling ; physiology ; Cell Differentiation ; physiology ; Cells, Cultured ; Dinoprostone ; metabolism ; Humans ; Osteoblasts ; cytology ; physiology ; Prostaglandin-Endoperoxide Synthases ; metabolism ; Shear Strength ; physiology ; Signal Transduction ; physiology

OBJECTIVETo study the gene expression profiles of traumatic occlusion in early stage with the animal model of rats.

METHODSThe occlusal surface of the upper left first molar of rat was raised by placing a stainless steel wire to induce occlusal trauma in the lower left first molar. After 24 hours, the alveolar bone tissue of the first molars at the both sides of rats' lower jaws were taken out under anesthesia. The different expressive genes were shown by genome-wide microarray, which comprises about 27 000 genes and analyzed the different expressive genes with Pathway and GO analysis, finally the results of the microarray were examined by real time-polymerase chain reaction (RT-PCR).

RESULTSIn the results of the study, 586 different expressions were found, of which the expressions of 166 genes increased and 420 genes decreased. 106 different pathways were involved with Pathway analysis and 270 different functional classification related to GO analysis.

CONCLUSIONThe balance of the lower alveolar bone is destroyed after 24 hours of traumatic occlusion. At early phase of the occlusal trauma, osteogenesis and bone formation in alveolar bone are inhibited, yet osteoblast genesis and bone resorption are not significant.

Alveolar Bone Loss ; Animals ; Bone Resorption ; Dental Occlusion ; Dental Occlusion, Traumatic ; Mandible ; Molar ; Osteoblasts ; Osteogenesis ; Rats ; Transcriptome

Objective To investigate the relationship between the expression of imprinted gene CDKN1C in placenta and the birth weight of neonates.Methods Twenty-nine term small for gestational age (SGA) neonates admitted to Peking University Third Hospital from January 1,2014 to December 31,2014 were recruited,and 29 appropriate for gestational age (AGA) neonates with a difference of not more than one week in gestational age served as controls.Fresh placental tissue was collected and the expression of imprinted gene CDKN1C mRNA in the placenta were detected by real-time fluorescence quantitative-polymerase chain reaction,and its protein expression was estimated by Western-blot.Chi-square test,independent-sample t test,Pearson's correlation analysis were used for statistical analysis.Results The CDKN1C mRNA expression level in SGA was significantly higher than that in AGA (0.133± 0.059 vs 0.100±0.046,t=2.401,P=0.020),so was the CDKN1C protein expression (0.280±0.043 vs 0.190±0.041,t=8.410,P=0.000).The CDKN1C mRNA expression levels were negatively correlated with birth weight in both groups (SGA group,r=-0.587,P=0.001;AGA group,r=-0.569,P=0.001),and the correlation was slightly stronger in SGA (r2=0.344) than in AGA (r2=0.324).The CDKN1C protein expression levels of the two groups were negatively correlated with birth weight (SGA group,r=-0.579,P=0.001;AGA group,r=-0.497,P=0.006),the correlation being stronger in SGA group (r2=0.335) than in AGA group (r2=0.247).The CDKN1C mRNA and protein expression levels of the two groups were negatively correlated with birth weight for gender,especially in males [mRNA:r2=0.293(male)vs r2=0.185(female);protein:r2=0.730 (male) vs r2=0.601(female)].Neither CDKN1C mRNA nor protein expression level was correlated to the placenta weight (mRNA:SGA group,r=0.119,P=0.540;AGA group,r=-0.069,P=0.722;protein:SGA group,r=0.126,P=0.515;AGA group,r=-0.247,P=0.196).Conclusions The expressions of CDKN1C mRNA and protein may be related to birth weight of term SGA neonates,especially in male infants.

Objective To explore a novel quantitative detection method for the concentration of specific IgG (sIgG) in food intolerance, taking egg sIgG detection for the example. Methods A total of 173 patients underwent food allergen sIgG detection were included in this study, and 78 healthy subjects were used as negative controls. The microtiter plates were coated with biotinylated bovine serum albumin (BSA) and linked with streptavidin. Then, the biotinylated egg antigen and specimen were successively added into the wells of plate.After washing, enzyme labeled anti-human IgG was added to establish an antigen indirectly coated liquid-phase reaction patterns of ELISA method. The concentration of the biotinylated allergens and enzyme labeled antibody were optimized and the reaction conditions were determined. This method was used to detect the sIgG in serum samples. Results The biotinylated egg white was selected as antigen, the optimal dilution rate was 1∶2 000,and the most suitable enzyme labeled antibody dilution ratio was 1∶12 000 in this method. The within-run and the between-run coefficients of variation were 4.83%-8.55%and 4.88%-7.93%respectively. The specificity is preferable, the species-crossed reaction rates with crab, cow milk and goat milk were＜10%. There was a good correlation between the assay developed in this study and the food intolerance detection kit provided by United States BIOMERICA Inc ( =0.977X+8.45, r=0.961, P＜0.05). Conclusion The detection method can be used to detect serum sIgG for egg intolerance patients with easy operation, highly accuracy and specificity. Furthermore, it showed the capacity of excellent repeatability and flexibility potential, which provided a good foundation for developing a kind of“personalized”random combination of food varieties ELISA kit.

OBJECTIVETo study the intercellular communication of alveolar bone during traumatic occlusion at early stage in rats.

METHODSThe occlusal surface of the upper left first molar of rat was raised by placing a stainless steel wire to induce occlusal trauma in the lower left first molar. After 24 hours, the alveolar bone tissues of the lower jaws first molars at the both sides were taken out under anesthesia The various 27 000 genes were identified with genome-wide microarray, and further were investigated with reverse transcription-polymerase chain reaction (RT-PCR) and Pathway analysis.

RESULTSTotal 586 gene were found to be changed, 106 different signal pathways got involved with Pathway analysis, including cell adhesion molecules(CAMS), adhesions junction, gap junction, focal adhesion and tight junction, and the cytokines associated with bone metabolism in above 5 signal pathways were all down-regulated.

CONCLUSIONAt the early phase of the occlusal trauma, intercellular communication in rat's alveolar bone were inhibited.

Alveolar Process ; Animals ; Bone and Bones ; Dental Occlusion ; Dental Occlusion, Traumatic ; Molar ; Rats

OBJECTIVETo explore the suitable level and action time of 17-beta estradiol and fluid shear stress (FSS) and their combined effect on the proliferation of rat osteoblasts in vitro.

METHODSMC3T3-E1 osteoblasts were adopted after subcultured and different concentrations of 17-beta estradiol and FSS values were applied respectively on MC3T3-E1, the suitable level of 17-beta estradiol and FSS were selected through MTT and alkaline phosphatase (ALP). Then the two factors at the suitable level were applied simultaneously to MC3T3-E1 to detect the proliferation activity.

RESULTSSeventeen-beta estradiol(10(-8) mol x L(-1) for 5 d and 12 x 10(-5) N FSS for 60 min exhibited better effects on the proliferation activity than the other groups respectively, and the combined effect of both factors was better than any single-factor treated group.

CONCLUSIONBoth 17-beta estradiol and FSS have a suitable threshold in promoting proliferation of osteoblasts, and two-factor treated group exhibits better effect than any other single-factor treated groups. Therefore 17-beta estradiol and FSS have a synergetic action on differentiation and proliferation of osteoblasts.

Alkaline Phosphatase ; Animals ; Cell Differentiation ; Estradiol ; Osteoblasts ; Rats ; Stress, Mechanical

Objective To explore the differentially expressed genes and related signaling pathways in MC3T3-E1 osteo-blasts in response to suitable fluid shear stress values and action time with cDNA microarrays. Methods MC3T3-E1 cells cultured on a cover slip were subjected to fluid shear stress using a parallel plate flow chamber. The harvested RNA was used for microarray hybridization comprising approximately 44 170 genes, as well as for the subsequent real-time quantitative polymerase chain reaction validation of expression levels for selected genes. Microarray results were analyzed by using both GO and Pathway analysis. Results Microarray analysis indicated that 884 differentially expressed genes were found. Among these genes, 444 were upregulated, whereas 440 were downregulated. The Notch signal and RIG-Ⅰ-like receptor signaling pathways were involved in the Pathway analysis. GO analysis mainly involved different functional classifications, such as prostaglandin biosynthesis, nitric oxide-mediated signal transduction, calcium mediated signal, and cellular immune response, among others. Conclusion The mechanism underlying the protective effect of fluid shear stress on MC3T3-E1 cells might be related to promoting cell survival- and inhibiting cell apoptosis-related signaling pathways and biological processes.

Antineoplastic Protocols ; China ; Humans ; Lymphoma, Large B-Cell, Diffuse ; therapy ; Treatment Outcome

Purpose: Titanium implants are widely used in the treatment of dentition defects; however, due to problems such as osseointegration failure, peri-implant bone resorption, and periimplant inflammation, their application is subject to certain restrictions. The surface modification of titanium implants can improve the implant success rate and meet the needs of clinical applications. The goal of this study was to evaluate the effect of the use of porous titanium with a chitosan/hydroxyapatite coating on osseointegration. Methods: Titanium implants with a dense core and a porous outer structure were prepared using a computer-aided design model and selective laser sintering technology, with a fabricated chitosan/hydroxyapatite composite coating on their surfaces. in vivo and in vitro experiments were used to assess osteogenesis. Results: The quasi-elastic gradient and compressive strength of porous titanium implants were observed to decrease as the porosity increased. The in vitro experiments demonstrated that, the porous titanium implants had no biological toxicity; additionally, the porous structure was shown to be superior to dense titanium with regard to facilitating the adhesion and proliferation of osteoblast-like MC3T3-E1 cells. The in vivo experimental results also showed that the porous structure was beneficial, as bone tissue could grow into the pores, thereby exhibiting good osseointegration. Conclusions Porous titanium with a chitosan/hydroxyapatite coating promoted MC3T3-E1 cell proliferation and differentiation, and also improved osseointegration in vitro. This study has meaningful implications for research into ways of improving the surface structures of implants and promoting implant osseointegration.