Microenvironmental stiffness mediates cytoskeleton re-organization in chondrocytes through laminin-FAK mechanotransduction / 国际口腔科学杂志·英文版

Microenvironmental biophysical factors play a fundamental role in controlling cell behaviors including cell morphology, proliferation, adhesion and differentiation, and even determining the cell fate. Cells are able to actively sense the surrounding mechanical microenvironment and change their cellular morphology to adapt to it. Although cell morphological changes have been considered to be the first and most important step in the interaction between cells and their mechanical microenvironment, their regulatory network is not completely clear. In the current study, we generated silicon-based elastomer polydimethylsiloxane (PDMS) substrates with stiff (15:1, PDMS elastomer vs. curing agent) and soft (45:1) stiffnesses, which showed the Young's moduli of ~450 kPa and 46 kPa, respectively, and elucidated a new path in cytoskeleton re-organization in chondrocytes in response to changed substrate stiffnesses by characterizing the axis shift from the secreted extracellular protein laminin β1, focal adhesion complex protein FAK to microfilament bundling. We first showed the cellular cytoskeleton changes in chondrocytes by characterizing the cell spreading area and cellular synapses. We then found the changes of secreted extracellular linkage protein, laminin β1, and focal adhesion complex protein, FAK, in chondrocytes in response to different substrate stiffnesses. These two proteins were shown to be directly interacted by Co-IP and colocalization. We next showed that impact of FAK on the cytoskeleton organization by showing the changes of microfilament bundles and found the potential intermediate regulators. Taking together, this modulation axis of laminin β1-FAK-microfilament could enlarge our understanding about the interdependence among mechanosensing, mechanotransduction, and cytoskeleton re-organization.

Disturbed bone remodelling activity varies in different stages of experimental, gradually progressive apical periodontitis in rats / 国际口腔科学杂志·英文版

Bone remodelling keeps going through the lifespan of human by bone formation and bone resorption. In the craniofacial region, mandibles act as the main force for biting and chewing, and also become susceptible to a common bone-loss disease, namely, apical periodontitis, once infected dental pulp is not treated timely, during which bone resorption occurs from the apical foramen to the apical bone area. Although conventional root canal treatment (RCT) can remove the most of the infection, chronical apical periodontitis due to incomplete removal of dental pulp and subsequent microleakage will become refractory and more challenging, and this process has scarcely been specifically studied as a bone remodelling issue in rat models. Therefore, to study chronical and refractory apical periodontitis owing to incomplete cleaning of infected dental pulp and microleackage in vivo, we establish a modified rat model of gradually progressive apical periodontitis by sealing residual necrotic dental pulp and introducing limited saliva, which simulates gradually progressive apical periodontitis, as observed in the clinical treatment of chronical and refractory apical periodontitis. We show that bone-loss is inevitable and progressive in this case of apical periodontitis, which confirms again that complete and sound root canal treatment is crucial to halt the progression of chronical and refractory apical periodontitis and promote bone formation. Interestingly, bone remodelling was enhanced at the initial stage of apical periodontitis in this model while reduced with a high osteoblast number afterwards, as shown by the time course study of the modified model. Suggesting that the pathological apical microenvironment reserve its hard tissue formation ability to some degree but in a disturbed manner. Hopefully, our findings can provide insights for future bone regenerative treatment for apical periodontitis-associated bone loss.

Preliminary study of assessment of mental health level among oral tumor patients and difference of relevant material basis / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the difference in mental health status of oral tumor patients and their spouses, and explore the differences on the basis of relevant materials.</p><p><b>METHODS</b>Forty patients with oral cancer, eighteen spouses, and thirty-five patients with oral benign tumor were diagnosed in the West China Hospital of Stomatology between December 2011 and August 2012 and assessed with symptom checklist-90 (SCL90) (the 5-grade scoring). Participants were assessed independently according to their conditions. Blood samples were obtained from the participants by syringe on the second admission day. A method was developed to determine the concentrations of catecholamine and glucocorticoid in the serum using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).</p><p><b>RESULTS</b>The scores for compel, depression and rests in the cancer group and benign tumor group were statistically significant (P<0.05). The scores for compel, dread and stubborn in the cancer group and their spouses were statistically significant (P<0.05). The differences between the total and other monomial factor scores were not statistically significant. However, the contents of epinephrine, norepinephrine, cortisone and hydrocortisone in the serum, as determined by HPLC-MS/MS, were significantly different (P<0.001).</p><p><b>CONCLUSION</b>Psychiatric factors do not show a simple factor effect on patients. Symptoms of patients may be based on tumorigenesis and developed in small molecules. Further research is required.</p>