BACKGROUND:Local administration of anti-tuberculosis drugs is a commonly used therapy. Due to the rapid absorption, the drugs cannot have the durable therapy effect; therefore, it is necessary to seek an optimal carrier material for the agents. OBJECTIVE:To review the new development for the carrier materials of anti-tuberculosis drugs. METHODS:A computer-based search of PubMed and VIP databases was performed by the first author to search articles related to sustained-released anti-tuberculosis drugs published from January 1990 to December 2014. The key words were osteoarticular tuberculosis; anti-tuberculosis; sustained-released drugs in English and Chinese, respectively. RESULTS AND CONCLUSION:Inorganic materials (calcium phosphate, calcium sulfate), polymer materials (polylactic acid, polyglycolic acid, polylactic-co-glycolic acid) and biomaterials (protein, glutin, alginates, chitin, demineralized bone matrix) are the main three kinds of carrier materials for anti-tuberculosis drugs. These carrier materials have their own advantages and disadvantages, which cannot be the optimal carrier materials. However, the complex of these materials is a promising technology for the optimal carrier materials in the future.

Objective A new type of bone graft material was constructed by combining calcium phosphate cement(CPC) with bone morphogenetic protein(BMP). In order to evaluate the feasibility to use this material to repair the segmental bone defect in clinic, the ability of CPC was compared with CPC/BMP in bone defects reconstruction by animal experiments. Methods The model of 15 mm bone defect was established in the middle shaft of the radius in 60 rabbits, of which 30 defects were implanted with CPC/BMP composites, 22 implanted with CPC, and the other 8 rabbits served as control group. The specimens were harvested separately at the end of 2, 4, 8, 16 and 24 weeks after operation. In order to observe the formation of new bone and the degradation process of the material, a series of examinations were carried out including of radiography, histomorphology, serum detection, energy dispersion analysis X-ray(EDAX), scanning electron microscope(SEM),bone density detection, mechanical measurement and inorganic substance detection. The results of CPC group and CPC/BMP group were compared on the same condition. Results All the animals survived after operation, and no reactions of toxicity were found. New bone formation was observed to be increasing significantly in CPC/BMP group with the time of implantation. Only little new bone formed in CPC group and no healing was found in the control group. By the end of 24 weeks, new bone had bridged the gap between the proximal and distal fragments in CPC/BMP group. In histomorphological detection, chondrocytes were found at the 2nd week, and woven bone at 4th week in CPC/BMP group. Remodeling of new lamellar bone and absorption of the composite material were observed at the 16th week, and the mechanical strength of the composite material reached almost to normal level at the 24th week. Calcification was significantly higher in CPC/BMP group than that in CPC group examined by EDAX, new bone density detection and measurement of inorganic substance in specimens. During the repairing process of bone defect, the material degraded while new bone formed, the speed of degradation of CPC/BMP was evidently higher than that of CPC group. Moreover, in the process of CPC degradation, the concentration of calcium in serum increased, and the concentration of phosphate in serum kept unchanged. Conclusion The CPC/BMP composite has great potential in bone defects repairing and could be used as a material for bone graft substitute in clinical patients.

Objective To investigate the effect of two kinds of injected biomaterial combined with bone morphological protein (BMP) on tendon-to-bone healing after anterior cruciate ligament reconstruction (ACL) in rabbits. Methods ACL reconstruction was performed bilaterally in 50 skeletally mature rabbits using long digital extensor tendon grafts. Injected fibrin glue (FG) or injected calcium phosphate cements (CPC) combined with BMP were implanted into the treated knee of each rabbit,with the contralateral knees as controls. Every three rabbits were killed at 2,6 and 12 weeks postoperatively for routine histological studies. The samples were processed through Micro CT and subsequent HE and toludine blue staining. The remaining 16 rabbits were sacrificed at 6 and 12 weeks. Their femur-tendon graft-tibia complexes were harvested for subsequent mechanical testing. Results Imageological results showed that 6 weeks after operation,bone mineral density (BMD) values in FG-bBMP group were higher than those in CPC-bBMP group. However,12 weeks after operation,BMD values in CPC-bBMP group were the highest in the three groups. Histological findings of the interface between the tendon and bone differed in the three groups. Two weeks after operation,more chondrocyte-like cells that were fairly disorganized were noted between the tendon and bone in FG-bBMP group. Six weeks after operation,mature bone formation around the tendon was observed in FG-bBMP group while more immature bone ingrew toward implanted tendon in CPC-bBMP group; at 12 weeks,more chondrocyte cells and new bone formation were seen in CPC-bBMP group while a small quantity of mature bone was around tendon in FG-bBMP group. In biomechanical evaluation,the maximum pull-out load of the tendon from the bone tunnel was significantly higher in the two treatment groups than in the control group 6 and 12 weeks after operation (P

[Objective]To study the differentiation of adipose-derived adult stem cells(ADASCs)into chondrocytes induced by TGF-?1 in the presence of different concentrations of serum in vitro.[Method]Adipose tissue-derived adult stem cells were isolated from rabbits subcutaneous adipose tissue using enzymatic digestion.The adipose tissue was minced and digested with collagenase type I,and the released cells were collected by density centrifugation and then placed in culture.After being passaged three times,ADASCs were induced to differentiate into chondrocytes by chondrogenic culture media containing 1% or 10% of FBS for 2 weeks.MTT,alkaline phosphatase toluidine blue staining and type Ⅱ collagen immunohistochemistry staining were then tested in both groups.Gray value was analyzed by Leica patho-image analysis system to observe if there was any difference in differentiative status between the two groups.[Result]MTT showed that the cells of 10% FBS group had higher proliferation activity than those of 1% FBS group(P

Objective To observe histomorphology of neo-cartilage obtained with tissue-engineering by combining calcium alginate gel and in vitro cultrue of chondrocytes. Methods Articular chondrocytes from the knee joints of 2-week-old New Zealand white rabbits were harvested, expanded in cell culture, and following the second generation of the culture, the chondrocyte suspension was mixed with calcium alginate gel resulting in a cell density of 5? 10 6/ml. Finally the mixture, which contained 1％ sodium alginate, 40 mmol/L calcium gluconate, 0.135 mol/L NaCl, 0.1 mol/L K 2HPO 4 and 5? 10 6 chondrocytes per milliliter, were injected into the dorsal subcutaneous tissue in rabbits of experimental groups (A and B). Animals of the control groups (C and D) were injected with calcium alginate without chondrocytes or chondrocytes without calcium alginate. Specimens were harvested at the 2nd and 4th week after injection, and stained with HE and toluidine blue. Results In the HE stained specimens in the experimental groups, proliferation of chondrocytes was demonstrated at the 2nd week and the formation of neo-cartilage at the 4th week after injection of calcium alginate chondrocyte-composite. Toluidine blue stained specimens showed positive staining of chondrocytes and cartilage matrix of neo-cartilage. In some animals injected with chondrocytes without calcium alginate, relative small amount of neo-cartilage was also formed and no neo-cartilage was observed in animals injected with calcium alginate without chondrocytes. Conclusion Injectable calcium alginate-chondrocyte-composite can induce tissue engineered neo-cartilage in allogenic animal.

BACKGROUND: Matrix material for cartilage tissue engineering exhibits too fast or too slow chondrocytes degradation in vivo, affecting tissue regeneration and shaping reconstruction, which has troubled scholars.OBJECTIVE: To amply bone marrow stromal cells (BMSCs) and induce them to chondrocytes in vitro, so as to study the feasibility of repairing articular cartilage defects in rabbits using poly(lactic-co-glycolic acid) (PLGA) loaded with BMSC-derived chondrocytes.DESIGN, TIME AND SETTING: Comparative experiment was performed at the Institute of Orthopaedics in the Fourth Military Medical University of Chinese PLA and the Center Laboratory of the Airforce General Hospital of Chinese PLA between June 2002 and June 2008.MATERIALS: A total of 36 two-month-old New Zealand white rabbits were used, and 4-6 mL bone marrow was aspirated from bilateral femoral trochanters in each animal. Primary culture and subcultures were done. In subcultures, the medium contained bone morphogenetic protein-2 (100 μg/L.), and high polymer hyaluronic acid was spread on bottom of the culture flasks in advance.In this way, the BMSCs were induced into chondrocytes and the third passage of cells at the adjusted density of 2.0×10~(10)/L wereco-cultured with PLGA for 24 hours, then PLGA-cell composites were prepared.METHODS: A defect of 4-mm in diameter and reaching medullary cavity were created in femoral condyles of 36 rabbits, and 36 right knees were treated with PLGA-cell composites, serving as experimental group, while 18 left knees with PLGA only as material group, and the other 18 knees remained untreated, as blank control group.MAIN OUTCOME MEASURES: At 4,8,12, 24 weeks after operation, the animals were euthanized and the newly formed tissues were observed macroscopically and microscopically, graded histologically, and analyzed statistically.RESULTS: Material group and blank control group shared identical outcomes of gross and histological observation, thus assigning into a control group. In the experimental group at 24 weeks, the defects were filled with white translucent cartilage tissue which appeared smooth and tenacious. The color and the luster were similar to that of normal cartilage, and was ill-demarcated from the surrounding normal cartilage. The cells on the surface paralleled to joint surface. Though the cells in the deep layer arranged disorderly, they tended to align vertically. The matrix was extensively stained. The subchondral bone formed.The tide mark basically recovered, and the new cartilage integrated with normal cartilage finely. In the control group, chondrocytes proliferated in the border, but in the bottom, there were mainly fibrous tissues. The histological grade of 12 and 24 weeks was different significantly from that of 4 and 8 weeks (P < 0.01). There were also significant differences between experimental group and control group at each time intervals after operation (P < 0.01).CONCLUSION: BMSCs were successfully induced into chondroncytes by use of bone morphogenetic protein-2 and high polymer hyaluronic acid. PLGA can be degraded and absorbed gradually while new cartilage tissues form. It can be used as a suitable scaffold material for repairing articular cartilage defects in tissue engineering.

Normal cells have limited proliferation ability.After certain cycles of proliferation,they will lose the response ability to growth factors and finally cease division and start the course of aging. In current opinion,lacking of the terminal end of a chromosome(telomere)is the cause for cells to loss the proliferation ability and leads cells to aging and death.The human telomerase catalytic subunit 1(hTERT)can activate telomemse which prolong DNAs of the terminal end of chmmosome and help cells gain genomic stabilization.The discoveries of telomere,telomerase and hTERT provide new idea for studying of cell aging and the findings are also applied in the establishment of immortal cell line. Also they may play an important role in the studv of biological feature of seed cell in tissue engineering and the establishment of cell bank.

Objective To investigate the therapeutic effect of anti-infecti ve reconstituted bone xenograft(ARBX)on osteomyelitis. Methods A proximal tibia os teomyelitis rabbit model was used. Twenty animals were randomly assigned to 4 gr oups and all of them were injected with staphylococcus aureus through a bone win dow. Two weeks postoperatively the animals underwent clearance of the focal lesi on, followed by implant of 3 pellets of ARBX containing 30 mg of gentamicin in g roup Ⅰ, 3 pellets of reconstituted bone xenograft (RBX) in conjunction with 30 mg of intramuscular gentamicin for 5 days in group Ⅱ, 3 pellets of RBX without antibiotic in group Ⅲ, and those in group Ⅳ were left without bone grafting. S pecimens were harvested 8 weeks after the above procedures and were then subject ed to gross observation, radiological, histological and bacteriological examinat ions to compare their therapeutic effect on osteomyelitis. Results 1) In group Ⅰ the bacteria counting and modified Norden scoring were by far the smallest am ong all 4 groups (P

[Objective]To explicate whether the telomerase activity is regulated by human telomerase reverse transcriptase (hTERT) in human bone marrow mesenchyme stem cells(hBMSC).[Method]hBMSC were cultured and transfected with eukaryotic expressing plasmid pCIneo-hTERT encoding hTERT. After selection with G418 to stabilize the transfection,expression of hTERT mRNA was detected with TR-PCR, detecting the expression of hTERT protein was detected with Western Bolt, and the telomerase activity in untransfected and transfected cells were detected by RT-PCR.[Result]The hMSCs grew well after transfecting plasmid pCIneo-hTERT.The cells began to suspend and die after the day of the G418 selection. At the tenth day,all the untransfected cells were dead, but the transfected cells began to clone proliferation. So the density of G418 subdued to 100 ?g/ml for maintaining selecting, at the twentieth day,there were obvious anti-G418 cell clones. After stable transfection, hTERT was expressed at mRNA and protein level in these anti-418 cell clones, and meanwhile telomerase activity was positive and obviously raise up in these transfected cells.[Conclusion]In human' bone marrow mesenchyme cells,telomerase could be activated by exogenous hTERT. This is a foundation to establish immortalized human bone marrow mesenchyme stem cell line.

[Objective]To explore the potential of a novel collagen I /chitosan /Nano?-tricalcium phosphate(?-TCP)bilayered scaffold for being used in tissue engineering(TE)of osteochondral repair.[Method]Bilayered scaffolds were produced with collagen Ⅰ,chitosan and?-TCP,using a special cross-linking and freeze drying method.The pore size,porosity and interpores of the scaffold were observed by scanning electron microscopy(SEM).Rabbit bone mesenchymal stem cells(BMSC)were isolated and amplified,then inoculated onto the scaffold.By SEM scanning,the condition of the cells adhering onto the scaffold was observed.The proliferation of the cells on the scaffolds was examined using MTT method,and the growth curve was drawn.The cell-scaffold composite were then induced to differentiate towards cartilage by 3-D culturing,and then implanted into muscle pouches 2 weeks later.The result was observed 6 weeks later by HE staining,toluidine blue staining and type Ⅱ collagen immunohistochemistry.[Result]The scaffold possessed high porosity and proper pore size,the porosity was above 95%.BMSC could adhere onto the scaffold well,and the proliferation rate of the cells on the scaffolds was perfectly good.After in vitro induction,BMSC-scaffold composite can differentiate toward cartilage ectopicly.[Conclusion]The novel collagen I /chitosan /?-TCP bilayered scaffold possesses good pore structure and biocompatibility,and will possibly become a new biomaterial of TE used for osteochondral repair.