Cartilage tissue engineering with demineralized bone matrix gelatin and fibrin glue hybrid scaffold: an in vitro study.

To develop a cartilage-like tissue with hybrid scaffolds of demineralized bone matrix gelatin (BMG) and fibrin, rabbit chondrocytes were cultured on hybrid fibrin/BMG scaffolds in vitro. BMG scaffolds were carefully soaked in a chondrocyte-fibrin suspension, which was polymerized by submerging the constructs into thrombin-calcium chloride solution. Engineered cartilage-like tissue grown on the scaffolds was characterized by histology, immunolocalization, scanning electron microscopy, biochemical assays, and analysis of gene expression at different time points of the in vitro culture. The presence of proteoglycan in the fibrin/BMG hybrid constructs was confirmed by positive toluidine blue and alcian blue staining. Collagen type II exhibited intense immunopositivity at the pericellular matrices. Chondrogenic properties were further demonstrated by the expression of gene-encoded cartilage-specific markers, collagen type II, and aggrecan core protein. The glycosaminoglycan production and hydroxyproline content of tissue grown on the fibrin/BMG hybrid scaffolds were higher than that of the BMG group. In conclusion, the fibrin/BMG hybrid scaffolds may serve as a potential cell delivery vehicle and a structural basis for cartilage tissue engineering.

Fluorine-induced apoptosis and lipid peroxidation in human hair follicles in vitro.

Fluoride is an essential trace element for human body; however, exposure to high amounts of fluoride has been documented to be correlated with an increasing risk of hair loss. To date, little is known about the mechanism(s) of how fluoride affects hair follicles. Here, we demonstrated that middle (1.0 mmol/L) and high (10.0 mmol/L) concentrations of sodium fluoride (NaF) significantly inhibited hair follicle elongation in vitro, but low NaF (0.1 mmol/L) showed little influence. Moreover, treatment with high levels of NaF resulted in a marked increase in terminal dUTP nick end labeling-positive cells in the outer layer of the outer root sheath, the dermal sheath, and the lower bulb matrix surrounding dermal papilla. Furthermore, the enhanced apoptosis was coupled with an increased oxidative stress manifested as higher malondialdehyde content. Additionally, the presence of selenium considerably antagonized the effects of middle NaF on hair follicles, with regard to either the suppression of hair growth or the induction of oxidative stress and apoptosis. In conclusion, exposure to high levels of fluoride compromises hair follicle growth and accelerate cell apoptosis in vitro. The toxicity of fluoride can be reduced by selenium, at least partially via the suppression of intracellular oxidative stress.

[Study of immunolipo-sodium morrhuate applied on human hemangioma endothelial cells in vitro].

PURPOSE: To explore the method of preparing immunolipo-sodium morrhuate and evaluate its effect on human hemangioma endothelial cells in vitro. METHODS: Using SPDP((N-Succinimidyl-3-(2-pyridyldithio)) propionate) as cross-linker, anti-VEGFR2/KDR monoclone antibody was combined to the liposome surface to prepare immunolipo-sodium morrhuate by extruding method, and then its effect on human hemangioma endothelial cells in vitro was observed by laser scanning confocal microscope, inverted microscope, Gimsa staining, transmission electron microscope, MTT and flow cytometry. RESULTS: The average diameter of the immunoliposome was 122.9 nm, which had a very good stability when compared with normal liposome, it had stronger and faster combining ability, its potential to induce apoptosis was much more prominent, and its toxic effect on human hemangioma endothelial cells was gentle, which was similar to normal liposome. CONCLUSION: We have prepared immunolipo-sodium morrhuate successfully, which has very good specific initiative targetting ability in vitro and can induce pervasive apoptosis of human hemangioma endothelial cells.

[Stress distribution analysis of the surface of condyle during simulated fracture healing of the neck of condyle by miniplate osteosynthesis].

OBJECTIVE: To find the reasons why patients always have temporomandibular disorders (TMD) after condylar fracture by analyzing the stress distribution change of the condylar surface whose subcondylar fracture ware fixed by miniplate during the whole healing process. METHODS: Analyzing the stress distribution change of the condylar surface whose subcondylar fracture were fixed by miniplate during the whole healing process by three-dimension finite element method (3D FEM). RESULTS: During the whole healing process of the fracture, the miniplate osteosynthesis was helpful to the biomechanics environment rehabilitation of the condylar local, but it still had difference with normal after fixing 12 weeks long. CONCLUSION: The difference of stress distribution of condylar surface that fractured and fixed by miniplate with normal may be part of the reason of TMD after the subcondylar fracture miniplate osteosynthesis.