[Comparison of three root canal disinfection methods for removal of Enterococcus faecalis under minimally invasive root canal treatment].

PURPOSE: To obtain an efficient and simple root canal disinfection method based on minimally invasive root canal treatment by comparing different root canal disinfection methods between minimally invasive root canal treatment and conventional root canal treatment. METHODS: Sixty-six extracted maxillary first molars were randomly divided into experimental group (computer-guided precision minimally invasive root canal treatment) and control group (conventional root canal treatment). All teeth were prepared to ProTaper universal F2, and Enterococcus faecalis infection models were established.Each group was randomly divided into three subgroups, sodium hypochlorite+EDTA root canal irrigation, sodium hypochlorite+EDTA+ultrasonic and sodium hypochlorite +EDTA +Er: YAG laser. After root canal disinfection,the samples were collected by paper tip method and cultured, and colony forming units (CFU) values of each sample were calculated. Then dentin debris was prepared and collected with F3 file. After being diluted and cultured, the CFU value was calculated. Statistical analysis was performed by SPSS 26.0 software package. RESULTS: Comparison of the amount of bacterial inner wall of root canal between the experimental group and the control group showed that the germicidal efficacy of group C and group B were significantly better than that of group A (P＜0.05), but there was no significant difference between group B and group C(P＞0.05). In the experimental group, there was significant difference between group B1, C1 and A1 (P＜0.05). The results of group B1 and C1 were lower than that of group A1, but there was no significant difference between group B1 and group C1(P＞0.05). In the control group, there were significant differences between group B2, C2 and A2 (P＜0.05). The results of group B2 and C2 were lower than that of group A2, but there was no significant difference between group B2 and C2(P＞0.05). Comparison of the amount of bacteria in dentin debris between the experimental group and the control group showed that the effect of group C was the best, followed by group B, and group A, and there were significant differences between three groups(P＜0.05). CONCLUSIONS: The disinfection effect of Er:YAG laser or ultrasound assisted computer-guided precision minimally invasive root canal treatment is similar to conventional root canal treatment, and Er:YAG laser is better than ultrasound in removing bacteria from dentinal tubules, which is more suitable for minimally invasive root canal treatment.

Possible two-photon absorption in the near-infrared region observed by cavity ring-down spectroscopy.

Two-photon absorption spectra are difficult to observe using direct absorption spectroscopy especially in the near-infrared region. Cavity ring-down spectroscopy is a promising absorption spectroscopy technique which has been widely applied to linear and saturated single-photon absorption spectra. In the present study, we report the observation of a possible two-photon absorption in the near-infrared using cavity ring-down spectroscopy, namely a two-photon resonance of methane. Using an optical frequency comb, the single-photon wavenumber of the double-quantum transition has been determined to be 182 207 682.645 MHz with a standard deviation of 75 kHz.

[Evaluation on the fracture resistance of dental tissues after guided plate-mediated precision minimally invasive root canal treatment].

PURPOSE: In order to achieve accurate and minimally invasive root canal treatment and enhance the fracture resistance of tooth tissue after root canal therapy, this study explores digital guided mediated minimally invasive root canal treatment and compares it with conventional root canal treatment to provide a more favorable method for clinical practice. METHODS: Forty freshly extracted first permanent molars were randomly divided into control group and experimental group. Teeth in the control group were treated with conventional root canal treatment, while teeth in the experimental group were treated with precise minimally invasive root canal treatment. The difference between the time of opening of the pulp chamber and the area of the open pores on the total area of the occlusal surface was compared. Loading test was carried out on the subjects using a universal testing machine, and the fracture resistence of the tooth tissues of the two groups were measured. Statistical analysis was performed using SPSS 24.0 software package. RESULTS: In the control group, the time required for opening the pulp chamber was (1.85±0.05) min, the open pore area was (9.18±0.48)% of the total occlusal area, and the load of the tooth tissue was (1.48±0.07) kN. In the experimental group, the time required was (0.72±0.10) min, the open pore area was (3.53±0.13)% of the total occlusal area, and the load of the tooth tissue was (1.81±0.03) kN. The higher the loading value, the stronger the fracture resistance of the tooth tissue. Compared with traditional root canal treatment, digital guided plate mediated minimally invasive root canal treatment had the advantages of short time, small access cavity and strong fracture resistance of tooth tissue. The difference between the two groups was significant (P<0.01). CONCLUSIONS: Digital guided plate-mediated accurate minimally invasive root canal treatment can reduce the occlusal area, shorten the operation time beside the chair, retain more healthy tooth tissue, enhance the fracture resistance of tooth tissue after root canal treatment, and improve the retention rate of affected teeth.

Risk Factors associated with Early Childhood Caries.

OBJECTIVE: To analyse factors associated with the susceptibility of early childhood caries (ECC), populations with a high risk of ECC were screened and guidance for ECC prevention was proposed. METHODS: A total of 392 children aged 24 to 71 months were selected for oral examination in Qingdao. Parents or guardians of the participants completed the questionnaires and decayed missing filled surface (dmfs) were recorded. Differences in caries condition and oral health behaviour in different families were compared. Risk factors related to ECC were screened. The subjects were finally grouped based on the obtained dmfs into three groups: caries-free, ECC and S-ECC (severe ECC). Association of risk factors with the caries status was analysed using the Kruskal-Wallis test, the chi-square test and logistic regression analysis. RESULTS: There were significant differences among the caries-free, ECC and S-ECC groups in three parameters: eating too many sweets each day, brushing before and after sleeping, and whether parents helped to brush (P < 0.01). Combined factors such as the parents' level of education, oral health knowledge, attitudes, the family's annual income, the age of children when they start to brush and not brushing regularly were also significantly related to ECC (P < 0.05). No significant differences were observed among the three groups for these factors, including birth condition and nursing state, physical condition of the mother during pregnancy, feeding situation, if a pacifier was used during sleep, duration of brushing, frequency of mouth rinsing after meals each day and brushing with fluoride toothpaste (P  > 0.05). CONCLUSION: Eating a lot of sweets, an incorrect brushing method, starting brushing at a later stage and not brushing regularly are susceptible factors for ECC. Emphasising oral health knowledge to parents and guardians, conducting proper brushing methods, limiting the frequency of sweets being eaten and avoiding an inappropriate habit of eating sweets are very important factors in the prevention of ECC.

Effects of CpG Oligodeoxynucleotide 1826 on transforming growth factor-beta 1 and radiation-induced pulmonary fibrosis in mice.

BACKGROUND: Cytosine-phosphate-guanine (CpG) oligodeoxyribonucleotides (ODNs) are synthetic DNA fragments containing unmethylated cytosine-guanine motifs with potential immune modulatory effects and have recently been suggested to enhance sensitivity to traditional therapies in lung cancer. This study aimed to examine the effects of CpG ODN1826 on transforming growth factor-beta 1(TGF-ß1) and radiation-induced pulmonary fibrosis in mice. METHODS: The radiation-induced pulmonary fibrosis mouse model was established by a single dose of 20 Gy, 6 MV X-rays exposure to the left lung. ICR mice were evenly randomized into four groups, comprising: a control group, a radiation group (RT group), a CpG group and a radiation combined with CpG ODN1826 group (RT + CpG group), with 40 mice in each group. CpG ODN1826 was intraperitoneally injected into mice at 1, 3, 5, 7 and 9 d post-irradiation. The mice were sacrificed at 1, 5, 15, 30 and 90 d post-irradiation. Paraffin sections of the radiated lung were subjected to H&E staining and Masson staining. The Ashcroft scale was used for quantitative histological analysis of fibrotic changes induced by irradiation. Concentrations of serum TGF-ß1 were determined by ELISA, and concentrations of Hydroxyproline(Hyp) in the lung were determined with the alkaline hydrolysis method. Relative gene expression of FoxP3 was determined by real-time PCR. RESULTS: The radiation-induced pulmonary fibrosis mouse model was successfully established. The serum concentrations of TGF -ß1 of RT group were higher than those of the RT + CpG group (t = 5.212, 7.126, 7.972 and 3.785, P < 0.05). The Hyp in the lung of RT group was higher than that of RT + CpG group (t = 4.606, P < 0.05). The relative expressions of FoxP3 gene in the lung of the RT group were higher than those of RT + CpG group (t = 8.395, 5.099 and 6.147, P < 0.05). CONCLUSIONS: CpG ODN1826 could reduce the serum concentrations of TGF-ß1 and the lung content of Hyp in radiation-induced pulmonary fibrosis, which might be related to the possibility that CpG ODN1826 can reduce expression of the FoxP3 gene.

Knee loading reduces MMP13 activity in the mouse cartilage.

BACKGROUND: Moderate loads with knee loading enhance bone formation, but its effects on the maintenance of the knee are not well understood. In this study, we examined the effects of knee loading on the activity of matrix metalloproteinase13 (MMP13) and evaluated the role of p38 MAPK and Rac1 GTPase in the regulation of MMP13. METHODS: Knee loading (0.5-3 N for 5 min) was applied to the right knee of surgically-induced osteoarthritis (OA) mice as well as normal (non-OA) mice, and MMP13 activity in the femoral cartilage was examined. The sham-loaded knee was used as a non-loading control. We also employed primary non-OA and OA human chondrocytes as well as C28/I2 chondrocyte cells, and examined MMP13 activity and molecular signaling in response to shear at 2-20 dyn/cm². RESULTS: Daily knee loading at 1 N for 2 weeks suppressed cartilage destruction in the knee of OA mice. Induction of OA elevated MMP13 activity and knee loading at 1 N suppressed this elevation. MMP13 activity was also increased in primary OA chondrocytes, and this increase was attenuated by applying shear at 10 dyn/cm². Load-driven reduction in MMP13 was associated with a decrease in the phosphorylation level of p38 MAPK (p-p38) and NFκB (p-NFκB). Molecular imaging using a fluorescence resonance energy transfer (FRET) technique showed that Rac1 activity was reduced by shear at 10 dyn/cm² and elevated by it at 20 dyn/cm². Silencing Rac1 GTPase significantly reduced MMP13 expression and p-p38 but not p-NFκB. Transfection of a constitutively active Rac1 GTPase mutant increased MMP13 activity, while a dominant negative mutant decreased it. CONCLUSIONS: Knee loading reduces MMP13 activity at least in part through Rac1-mediated p38 MAPK signaling. This study suggests the possibility of knee loading as a therapy not only for strengthening bone but also preventing tissue degradation of the femoral cartilage.

Rational design of an "OFF-ON" phosphorescent chemodosimeter based on an iridium(III) complex and its application for time-resolved luminescent detection and bioimaging of cysteine and homocysteine.

Biothiols, such as cysteine (Cys) and homocysteine (Hcy), play very crucial roles in biological systems. Abnormal levels of these biothiols are often associated with many types of diseases. Therefore, the detection of Cys (or Hcy) is of great importance. In this work, we have synthesized an excellent "OFF-ON" phosphorescent chemodosimeter 1 for sensing Cys and Hcy with high selectivity and naked-eye detection based on an Ir(III) complex containing a 2,4-dinitrobenzenesulfonyl (DNBS) group within its ligand. The "OFF-ON" phosphorescent response can be assigned to the electron-transfer process from Ir(III) center and C^N ligands to the DNBS group as the strong electron-acceptor, which can quench the phosphorescence of probe 1 completely. The DNBS group can be cleaved by thiols of Cys or Hcy, and both the (3)MLCT and (3)LC states are responsible for the excited-state properties of the reaction product of probe 1 and Cys (or Hcy). Thus, the phosphorescence is switched on. Based on these results, a general principle for designing "OFF-ON" phosphorescent chemodosimeters based on heavy-metal complexes has been provided. Importantly, utilizing the long emission-lifetime of phosphorescence signal, the time-resolved luminescent assay of 1 in sensing Cys was realized successfully, which can eliminate the interference from the short-lived background fluorescence and improve the signal-to-noise ratio. As far as we know, this is the first report about the time-resolved luminescent detection of biothiols. Finally, probe 1 has been used successfully for bioimaging the changes of Cys/Hcy concentration in living cells.

An in situ autologous tumor vaccination with combined radiation therapy and TLR9 agonist therapy.

PURPOSE: Recent studies have shown that a new generation of synthetic agonist of Toll-like receptor (TLR) 9 consisting a 3'-3'-attached structure and a dCp7-deaza-dG dinucultodie shows more potent immunostimulatory effects in both mouse and human than conventional CpG oligonucleotides. Radiation therapy (RT) provides a source of tumor antigens that are released from dying, irradiated, tumor cells without causing systemic immunosuppression. We, therefore, examined effect of combining RT with a designer synthetic agonist of TLR9 on anti-tumoral immunity, primary tumor growth retardation and metastases in a murine model of lung cancer. METHODS: Grouped C57BL/6 and congenic B cell deficient mice (B(-/-)) bearing footpad 3LL tumors were treated with PBS, TLR9 agonist, control oligonucelotide, RT or the combination of RT and TLR9 agonist. Immune phenotype of splenocytes and serum IFN-γ and IL-10 levels were analyzed by FACS and ELISA, 24 h after treatment. Tumor growth, lung metastases and survival rate were monitored and tumor specific antibodies in serum and deposition in tumor tissue were measured by ELISA and immunofluorescence. RESULTS: TLR9 agonist expanded and activated B cells and plasmacytoid dendritic cells in wild-type mice and natural killer DCs (NKDCs) in B cell-deficient (B(-/-)) mice bearing ectopic Lewis lung adenocarcinoma (3LL). Combined RT with TLR9 agonist treatment inhibited 3LL tumor growth in both wild type and B(-/-) mice. A strong tumor-specific humoral immune response (titer: 1/3200) with deposition of mouse IgG auto-antibodies in tumor tissue were found in wildtype mice, whereas the number of tumor infiltrating NKDCs increased in B(-/-) mice following RT+ TLR9 agonist therapy. Furthermore, mice receiving combination therapy had fewer lung metastases and a higher survival than single treatment cohorts. CONCLUSIONS: Combination therapy with TLR9 agonist and RT induces systemic anti-tumoral humoral response, augments tumoral infiltration of NKDCs, reduces pulmonary metastases and improves survival in a murine model of 3LL cancer.

Single polymer-based ternary electronic memory material and device.

A ternary polymer memory device based on a single polymer with on-chain Ir(III) complexes is fabricated by combining multiple memory mechanisms into one system. Excellent ternary memory performances-low reading, writing, and erasing voltages and good stability for all three states-are achieved.

Progress of oral sequelae during head-neck radiotherapy.

OBJECTIVE: To evaluate xerostomia, mucositis and dental caries during head and neck radiotherapy. METHODS: Twenty patients with nasopharyngeal carcinoma were included. Oral examinations were conducted before radiotherapy, after dosage of 2000 cGy irradiation, immediately after the termination of radiotherapy, and 1 month and 6 months after termination of the radiotherapy. Oral hygiene instruction, effective oral care and dental intervention were performed during the treatment. Salivary flow rate was evaluated by modified Schirmer's test. Xerostomia, mucositis and dental caries status were evaluated based on oral examinations. RESULTS: Salivary flow rate decreased significantly after the first dosage of 2000 cGy, and was aggravated with the increase in irradiation dosage until the termination of radiotherapy. Xerostomia and mucositis were observed in parallel with the reduction of saliva flow rate, and were aggravated with the increase in irradiation dosage. Mucositis began to recover within 1 month after the termination of radiotherapy and fully recovered within 6 months after the termination of the radiotherapy. Six months after the termination of irradiation, new carious lesions were detected in two patients. CONCLUSION: Oral sequelae developed during radiotherapy of the head and neck. Oral health instructions and effective intervention were essential before, during and after the radiotherapy.

Simple conjugated polymers with on-chain phosphorescent iridium(III) complexes: toward ratiometric chemodosimeters for detecting trace amounts of mercury(II).

For the development of excellent optical probes for mercury(II), a series of simple conjugated polymers that contain phosphorescent iridium(III) complexes as receptors for mercury(II) were designed and synthesized. These conjugated polymers showed energy transfer from the polymer host to iridium(III) complex guest in both solution and the solid state. Unexpectedly, they can work as excellent polymer chemodosimeters for mercury(II) by utilizing the mercury(II)-induced decomposition of iridium(III) complex. They exhibit a pronounced optical signal change with switchable phosphorescence and fluorescence, even when the concentration of a solution of mercury(II) in THF was as low as 0.5 ppb. With the addition of mercury(II), the phosphorescent emission intensity of iridium(III) complexes was quenched completely. As the emission from polymer backbones increased, the emission wavelength was redshifted simultaneously, thereby realizing ratiometric detection. Excellent selectivity toward mercury(II) over other potentially interfering cations was also realized. In addition, an obvious emission color change of polymer solution from red to yellow-green was observed, thus realizing a "naked-eye" detection of mercury(II). More importantly, the solid films of these polymer chemodosimeters also exhibited high sensitivity and rapid response to mercury(II), thereby demonstrating the possibility of the fabrication of sensing devices with fast and convenient detection of mercury(II). The sensing mechanism was also investigated in detail. This is the first report on chemodosimeters based on conjugated polymers with phosphorescent iridium(III) complexes.

Cationic iridium(III) complex containing both triarylboron and carbazole moieties as a ratiometric fluoride probe that utilizes a switchable triplet-singlet emission.

A novel cationic Ir(III) complex [Ir(Bpq)(2)(CzbpyCz)]PF(6) (Bpq=2-[4-(dimesitylboryl)phenyl]quinoline, CzbpyCz = 5,5'-bis(9-hexyl-9H-carbazol-3-yl)-2,2'-bipyridine) containing both triarylboron and carbazole moieties was synthesized. The excited-state properties of [Ir(Bpq)(2)(CzbpyCz)]PF(6) were investigated through UV/Vis absorption and photoluminescence spectroscopy and molecular-orbital calculations. This complex displayed highly efficient orange-red phosphorescent emission with an emission peak of 583 nm and quantum efficiency of Phi=0.30 in dichloromethane at room temperature. The binding of fluoride ions to [Ir(Bpq)(2)(CzbpyCz)]PF(6) can quench the phosphorescent emission from the Ir(III) complex and enhance the fluorescent emission from the N--N ligand, which corresponds to a visual change in the emission from orange-red to blue. Thus, both colorimetric and ratiometric fluoride sensing can be realized. Interestingly, an unusual intense absorption band in the visible region was observed. And the detection of F(-) ions can also be carried out with visible light as the excitation wavelength. More importantly, the linear response of the probe absorbance change at lambda=351 nm versus the concentration of F(-) ions allows efficient and accurate quantification of F(-) ions in the range 0-50 microM.

Development and validation of a motion and loading system for a rat knee joint in vivo.

The influence of biomechanical stimuli on modulating cartilage homeostasis is well recognized. However, many aspects of cellular mechanotransduction in cartilage remain unknown. We developed a computer-controlled joint motion and loading system (JMLS) to study the biological response of cartilage under well-characterized mechanical loading environments. The JMLS was capable of controlling (i) angular displacement, (ii) motion frequency, (iii) magnitude of the axial compressive load applied to the moving joint, and it featured real-time monitoring. The accuracy and repeatability of angular position measurements, the kinematic misalignment error as well as the repositioning error of the JMLS were evaluated. The effectiveness of the JMLS in implementing well-defined loading protocols such as moderate Passive Motion Loading (PML) and increased Compressive Motion Loading (CML) were tested. The JMLS demonstrated remarkable accuracy and reliability for the measurement and kinematics tests. Moreover, the effectiveness test demonstrated the ability of the JMLS to produce an effective stimulus via PML that led to the suppression of the catabolic effects of immobilization. Interestingly, the biological response of the CML group was catabolic and exhibited a pattern similar to that observed in the immobilization group. This novel non-invasive system may be useful for joint biomechanics studies that require different treatment conditions of load and motion in vivo.

Suppression of EDAG gene expression by phorbol 12-myristate 13-acetate is mediated through down-regulation of GATA-1.

EDAG, a hematopoietic tissue-specific protein, is involved in the regulation of proliferation, differentiation and apoptosis of hematopoietic cells. In this study, a dose-dependent inhibition of EDAG expression by PMA was observed in K562 cells. The responsive element for the PMA-induced inhibition was contained in the region between -211 and +32bp of the EDAG gene promoter. By oligonucleotide-directed mutagenesis, EMSA, ChIP and transient transfection assays, we found that two tandem repeat GATA-1 sites in the promoter of EDAG gene played an important role in the PMA-mediated down-regulation of the EDAG gene expression in K562 cells. The kinetics of EDAG expression during PMA induction showed that the levels of EDAG expression were down-regulated concomitantly with GATA-1 down-expression. Decreased GATA-1 expression by siRNA reduced expression of EDAG in K562 cells, and restored expression of GATA-1 significantly rescued EDAG expression from PMA-mediated suppression. Overexpression of EDAG in K562 cells inhibited the megakaryocytic differentiation induced by PMA which raised the interesting possibility that PMA induced K562 cells differentiation toward megakaryocytic phenotype through, at least in part, the inhibition of EDAG expression. In vivo analysis confirmed that EDAG was highly expressed in primitive progenitor cells and down-regulated in megakaryocytes which was consistent with the expression pattern of GATA-1. Furthermore, PKC and MAPK specific inhibitors treatment attenuated the down-regulation of EDAG induced by PMA. Taken together, these results suggest that the inhibition of the EDAG gene by PMA is mediated through down-regulation of transcription factor GATA-1 and involved the PKC/MAPK signaling pathway.

[Effect of three protective agents on edge closeness of glass ionomer cements].

PURPOSE: To observe the effect of three protective agents on edge closeness of glass ionomer cements filling in vitro. METHODS: Eighty freshly extracted human molars were randomly divided into A and B groups(40 molars each group). The teeth cavities were prepared at 1/3 part to buccal gingiva of each molar and those of A group were filled with GC Fuji IX and those of B group with another glass ionomer cement. A and B groups were respectively divided into three experiment groups and one control group(A1/B1). The filling surfaces of three experimental groups were separately coated with vaseline(A2/B2), cocoa butter(A3/B3), biscover (A4/B4). After thermal cycling(x 30, 5-55 degrees centigrade), the depth of dye penetrating into the teeth was observed through an optical microscope. The data was analyzed with rating information on diverse groups of the rank and testing, using SPSS13.0 software package. RESULTS: Different dye penetration degrees were shown between filling material and cavity walls among each group, while the degrees of dye penetration of experimental groups were significantly slighter than those of corresponding control group(P<0.05), and there was no difference among experimental groups (P>0.05). CONCLUSION: The three protective agents can increase the edge closeness of glass ionomer cement filling.

Oscillating Couette flow for in vitro cell loading.

Synovial joints are loaded by weight bearing, stretching, and fluid-driven shear. To simulate in vitro fluid-driven shear, we developed an "oscillating Couette flow mechanical shear loader". Oscillating Couette flow mimics relative motion of articular surfaces; hence, characterizing flow-induced shear by the loader enhances understanding of mechanotransduction in the joint tissue. Here, the analytical and computational models for an oscillating Couette flow were used to predict time-varying shear distribution on a plate surface, applying numerical simulation to evaluate the effects of finite plate dimension in a 2D flow. Shear stress on the plate was significantly different from that in simpler models (unbounded plates and viscous low-frequency flow). High-stress spots appeared near the leading and trailing edges of a moving plate, and a relatively uniform shear region was restricted to the interior area. Stress prediction in an example experimental geometry is presented, where the frequency and finite width effects are feasibly accounted.

Effects of high-impact mechanical loading on synovial cell cultures.

Cartilage metabolism in response to mechanical loading is an important subject in sports science and medicine. In animal studies high-impact exercise is known to stimulate bone adaptation and increase bone mass. However, mechanical impacts potentially induce tissue swelling and occasionally degradation of connective tissues in synovium and articular cartilage. These detrimental outcomes should be properly evaluated clinically and biochemically. Using two synovial cell cultures derived from normal and rheumatic tissues, we examined the biochemical effects of impulsive mechanical loads on expression and activities of influential proteolytic enzymes in joints, matrix metalloproteinases (MMPs), and their natural inhibitors, tissue inhibitors of metalloproteinases (TIMPs). The molecular analysis demonstrates that an impact factor (Im ), the ratio of the maximum force to weight, served as a good indicator for assessment of the inflammatory responses. The results showed that high impact above Im = 40 to 80 elevated not only expression but also enzymatic activities of MMPs. Key PointsHigh-impact loading elevated expression and activities of MMPs in synovial cell cultures.The impact factor was used to define in vitro intensity of high-impact loading.

CITED2-mediated regulation of MMP-1 and MMP-13 in human chondrocytes under flow shear.

CITED2 (CBP/p300-interacting transactivator with ED-rich tail 2) is a member of the Cited family of nuclear regulators, previously known as mrg1 (melanocyte-specific gene-related gene 1). CITED2 is inducible by varying stimuli including lipopolysaccharide, hypoxia, and cytokines such as interleukin 9 and interferon gamma. Using the immortalized human chondrocyte cell line, C-28/I2, we investigated whether CITED2 could be responsive to mechanical stimuli, and if so, whether CITED2 could mediate shear-driven regulation of matrix metalloproteinase (MMP) genes. The C-28/I2 cells were cultured under flow shear at 1-20 dyn/cm2, and the role of CIT-ED2 in regulation of MMPs was examined using the plasmids encoding sense and antisense CITED2 DNA sequences. The results showed that flow shear at 5 dyn/cm2 increased CITED2 mRNA and protein levels and down-regulated MMP-1 and MMP-13 mRNA and protein levels as well as enzyme activities. Consistent with the coordinated expression patterns of CITED2 and MMPs, overexpression of CITED2 repressed MMP-1 and MMP-13 mRNA levels and activities, whereas antisense CITED2 plasmids prevented the shear-induced down-regulation of MMP expression. Interleukin-1beta induced the formation of p300-Ets-1 complexes without affecting expression of CITED2. Transforming growth factor-beta as well as flow shear at 5 dyn/cm2 stimulated not only the expression of CITED2 but also the association of CIT-ED2 with p300 by dissociating Ets-1 from p300. These results indicate that CITED2 plays a major role in shear-induced down-regulation of MMP-1 and MMP-13 via a transforming growth factor-beta-dependent pathway.