OBJECTIVETo construct a mineralized collagen based composite by biomimetic synthesis for bone tissue engineering.

METHODSUsing the molecular collagen as the template, the calcium phosphate is deposited on it to produce a mineralized collagen based composite, then is combined with minute amount of poly lactic acid (PLA), the three-dimensional scaffold composite is prepared by liquid phase separation. Using osteoblast culture technique, the biocompatibility of this biomaterial in vitro is detected by x-ray diffraction, SEM, TEM, fluoroscopy and CLSM.

RESULTSBoth degree and the size of crystals in the composite are low, which are similar to that of nature bone. It possesses porous structure and the porosity of the composite is high. The typical fibrillar microstructure is self-assembled of the collagen and the nano-crystal hydroxyapatite (HA) in the composite, moreover, the x-ray diffraction graphic of HA crystal shows the [002]-oriented.

CONCLUSIONSThe biomimetic three-dimensional composite can serve as one of the optimal scaffold material for bone tissue engineering both on structure and on property.

Animals ; Animals, Newborn ; Biocompatible Materials ; chemistry ; Bone Substitutes ; Calcium Phosphates ; Cells, Cultured ; Collagen ; chemistry ; Lactic Acid ; chemistry ; Nanotechnology ; Osseointegration ; Osteoblasts ; cytology ; Polyesters ; Polymers ; chemistry ; Rats ; Rats, Wistar ; Tissue Engineering

OBJECTIVETo investigate the effect of nano-hydroxyapatite/collagen (nHA/collagen) composite as a graft extender and enhancer when combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) on lumbar intertransverse fusion in rabbits.

METHODSSixty-four adult female New Zealand white rabbits, aged 1 year and weighing 3.5-4.5 kg, underwent similar posterolateral intertransverse process arthrodesis and were randomly divided into 4 groups based on different grafts: autogenous cancellous bone alone (ACB group), nHA/collagen alone (HAC group), half autogenous cancellous bone and half nHA/collagen (ACB+HAC group) and nHA/collagen combined with rhBMP-2 (HAC+BMP group). The fusion masses were analyzed by manual palpation, radiography, biomechanical testing and histological examination.

RESULTSFusion was observed in 4 cases in the 6th week and in 5 cases in the 10th week after surgery in ACB group. No case showed fusion in HAC group. In ACB+HAC group, there was fusion in 3 cases in the 6th week and in 4 cases in the 10th week after surgery. In HAC+BMP group, fusion in 1 case was found in the 4th week, in 5 cases in the 6th week and in 6 cases in the 10th week after surgery. It suggested that ACB, ACB+HAC and HAC+BMP groups showed similar fusion ratio and mechanical strength in the 6th and 10th week after surgery. According to the microstructure analysis of the samples, nHA/collagen had no negative effect when implanted together with ilium autograft. In HAC+BMP group, new bone-like tissue was observed in the 2nd week postoperatively, and nearly all of the implanted composites were replaced by mature bone matrix and new bones in 10th week postoperatively.

CONCLUSIONSThe nHA/collagen, especially combined with rhBMP-2, is a promising bone substitute, for it has quick biodegradation, fine bone-bending ability, and high osteoconductivity on posterolateral spinal fusion in rabbits.

Analysis of Variance ; Animals ; Biomechanical Phenomena ; Bone Morphogenetic Protein 2 ; Bone Morphogenetic Proteins ; pharmacology ; Disease Models, Animal ; Durapatite ; pharmacology ; Female ; Lumbar Vertebrae ; drug effects ; surgery ; Osseointegration ; drug effects ; Probability ; Rabbits ; Sensitivity and Specificity ; Spinal Fusion ; methods ; Tensile Strength ; Transforming Growth Factor beta

Objective To explore the possible role of voltage-gated potassium channel-interacting protein 1 (KChIP1) in the pathogenesis of epilepsy. Methods Sprague Dawley female adult rats were treated with pentylenettrazole (PTZ) to develop acute and chronic epilepsy models. The approximate coronal sections of normal and epilepsy rat brain were processed for immunohistochemistry. Double-labeling confocal microscopy was used to determine the coexistence of KChIP1 and gamma-aminobutyric acid (GABA). Results KChIP1 was expressed abundantly throughout adult rat brain. KChIP1 is highly co-localize with GABA transmitter in hippocampus and cerebral cortex. In the acute PTZ-induced convulsive rats, the number of KChIP1-postive cells was significantly increased especially in the regions of CA1 and CA3 (P < 0.05); whereas the chronic PTZ-induced convulsive rats were found no changes. The number of GABA-labeled and co-labeled neurons in the hippocampus appeared to have no significant alteration responding to the epilepsy-genesis treatments. Conclusion KChIP1 might be involved in the PTZ-induced epileptogenesis process as a regulator to neuronal excitability through influencing the properties of potassium channels. KChIP1 is preferentially expressed in GABAergic neurons, but its changes did not couple with GABA in the epileptic models.