| Background:Osteosarcoma is a common human malignancy in the period 15-20 years old prone. Osteosarcoma patients before the 1970s, mainly through surgery, but less than 20% the survival rate after surgical resection of the tumor. The world’s most populous countries are China, due to the bone cancer cause death or disability, the number of functional disorders are also increasing year by year, ranking first in all countries of the world.Surgery on bone tumors, the main problem lies not only in the remaining part of the inevitable after surgery without resection of the tumor cells which is a great risk of recurrence, but there is a big downside is the surgical resection the tumor while causing the weight-bearing bone defect. Some occur in a particular part of the tumor, especially spinal tumors because of its particular parts occur causing their removal is often difficult, in addition, tumor tissue as well as skip metastasis during surgery contact with these tissues and normal tissue structure brings medical borne spread, may lead to local recurrence of the tumor after surgery. Thus, in the bone tumor resection often requires chemotherapy in clinical currently the most widely used traditional chemotherapy drugs such as doxorubicin, cisplatin, vinca alkaloids these drugs not only has anti-tumor activity, but also because of their onset non-selective for the human body’s various tissues and organs to bring the corresponding side effects of conventional therapeutic doses of chemotherapy drugs on the human body can produce significant side effects such as bone marrow transplant, cardiac toxicity, gastrointestinal side effects and so on, these side effects lower the patient’s compliance, easily lead patient refused treatment. Chemotherapy drugs usually have time and dose effects, improve concentration and prolong the half-life often can enhance the anti-tumor capabilities, but the dose and time to improve and extend generally bring more serious or even fatal side effects. In the long clinical practice can improve people’s desire to obtain a local drug concentration, to extend the duration of action of the drug new chemotherapy drugs in order to reduce chemotherapy-related side effects and improve the efficiency of chemotherapy. With the development of pharmaceutical formulation technology, the concept of local sustained release of drugs have been proposed, the idea is to slow-release drugs, prolonged release of the drug and the local release of drugs, improve the specificity of drug onset time; while the rapid development of tissue engineering technology the local drug release and biomimetic artificial bone material prepared by combining the implant can become after surgery to repair a partial weight-bearing bone defects caused by the administration of the selective targeting simultaneously. This idea for the treatment of bone tumors provides the means.Novel pharmaceutical topical slow release system can be widely used in the treatment of tumors, which is in a series of sustained release pharmaceutical biocompatible, biodegradable inorganic base or an organic material on the chemotherapy drugs commonly used in clinical combined, by different routes of administration implanted into a specific tissue, thereby achieving specificity onset purposes. locally sustained-release drug can be of local residual tumor cells, foci may act longer, the drug is not required by biological metabolism, tumor cells in a longer exposure time at higher concentrations of a chemotherapeutic drug, a great enhancing the therapeutic effect of the drug, as opposed to the traditional route of administration while it avoids the long run intravenous drug-induced systemic toxicity. Patients with advanced cancer or metastatic cancer patients who can not tolerate chemotherapy, sustained-release drugs in the local selective implantation dose may be increased, local release of drugs act directly on bone tumor longer, which is to improve end-stage cancer patients quality of life also has some help.However, the current conventional drug delivery system for the existence of the many shortcomings:a biocompatible delivery system is poor, generate significant immune system response after implantation; the rate of two drug delivery system, the packet is low. composite difficulty; the low dose of the drug compound, sustained release time is not ideal; the poor drug stability. The rapid development of nanotechnology, which greatly promoted the progress of various interdisciplinary applications of nanotechnology significantly improve local sustained release drug safety and effectivenessNanoparticles has a unique characterization of physical and chemical properties, a small size, so that the volume of such particles more easily penetrate cell barrier into the tissue space, Cells more easily be swallowed, and the nanoparticles can also increase the stability and solubility of the drug, while improving the rate of renal clearance plays an important role. In tumor tissue based retention (EPR effect) on the nano-drugs can selectively increase specificity by endocytosis through ligand-induced cell surface into the drug, so that a substantial increase in the therapeutic effect and reduce tumor resistance, but also can reduce the damage to non-tumor tissue. And reduce toxicity. Also because nanomaterials have unique small size and surface effects, such nanoscale hydroxyapatite material may osteoblasts, the bone tissue to provide a good environment for the growth, so the the bone conduction properties compared to conventional materials with obvious advantages.Locally sustained release drug concept in the development of tissue engineering, nanotechnology and drug technology, you can continue to expand the advantage to develop a better sustained release drug and carrier material. Our group built ADM-PLGA microspheres contained nano hydroxyapatite collagen scaffolds, their characterization and bone repair and inhibit the ability of tumor cells were tested and verified.Objective:Prepared by carrying adriamycin (ADM) polylactic acid-glycolic acid (PLGA) nanoparticles of nano-hydroxyapatite/collagen scaffolds (ADM-PLGA-NHAC), and experimental verification of this material relative performance and anti-tumor ability and the bone repair capacity, providing new tools for the clinical treatment of osteosarcoma, based clinical trial materials to lay a solid foundation.Methods:1. Double emulsion-solvent evaporation method to process adriamycin (ADM)-polylactic acid-glycolic acid (PLGA) release microspheres; nano-hydroxyapatite/ collagen scaffolds (NHAC) by freeze-drying of nano hydroxyapatite stone and as raw material for the preparation of collagen, joined ADM-PLGA microspheres during the preparation of prepared NHAC contained ADM-PLGA nanospheres of nano-hydroxyapatite/collagen scaffolds (ADM-PLGA-NHAC). After the completion of the preparation of the material for testing in vitro and its performance2. New Zealand white rabbits critical bone defect model chosen as the experimental animal model, experimental groups:group A bone defects as a control group; group C ADM-PLGA-NHAC; group B NHAC. The first eight weeks and 12 weeks after the drawn parallel X-ray examination, the resulting X-ray results according to Lane-Sandhu standard healing of bone defects were evaluated; X-ray examination after completion of the bone specimens in each group were Micro-CT scan for 3-D reconstruction, then after the scan data into Micro-CT analysis software comes with BMD value analysis; bone specimens for histological and scanning electron microscopy to determine situation of the bone repair3. After recovery MG63 cells syringe injected subcutaneously into nude mice, mice with a sharp knife to cut slices of tumor after tumor implantation random materials, measuring tumor weight and tumor volume calculation termination of the experiment; the tumor paraffin sections for HE staining of tumor metastasis, necrosis and cardiac toxicity, tumor tissue necrosis rate TUNEL assay and calculated.4. All statistical analysis by SPSS 13.0 software. Specific data are as mean± standard deviation (X±SD), said data among groups using ANOVA analysis (One-way ANOVA), groups were compared using LSD method (least significant difference), if the variance is using Dunnett’s T3 test method; if the P-value<0.05, we can consider the difference is statistically significant.Results:1.The research team obtained by emulsion evaporation method ADM-PLGA nanospheres are spherical, the average particle size of about 319.5nm±11.17nm, drug loading rate (6.42±0.28)%. Using the freeze-drying method ADM-PLGA nanoparticles and nano-hydroxyapatite/collagen scaffolds (ADM-PLGA-NHAC) complex, pore size of this material is about 100-200um, porosity up to about (82.3± 4.6)%, Release curve shows the drug did not show a significant burst phenomenon within 24h drug release rate of about 17.6% of the material in the 28d sustained slow release of ADM, and the release concentration is relatively stable. By living-dead staining and anti-tumor effects of CCK8 assay material showed that extracts ADM-PLGA-NHAC materials at significantly inhibited the growth of MG63 cells.2. In the 8 eight weeks and 12 weeks after implantation material drawn from X-ray, three-dimensional reconstruction and BMD values, the results show:Group C and Group D is not no significant difference in the degree of bone healing. A group show no obvious bone healing, group B (NHAC group) have not yet seen the degradation of the filling material and scattered in a large number of irregular start integration of new bone tissue, new bone tissue therebetween, group C (paraffin histology in detection ADM-PLGA-NHAC group) the degree of degradation of the material close to the group B, but the degree of integration of new bone and new bone tissue difference in group B. A 12-week group showed a small amount of new bone tissue irregularities at the edge of the bone defect, and group B, group C were seen more mature bone tissue and bone tissue similar integrated into the film and a lot of new bone and collagen and extensive integration flaky, partial degradation yet still see a small amount of filler material, the two groups showed no significant immune response.3. When the experiment is terminated drawn first to the naked eye there is a large lung tissue metastases, and tumor weighing, measuring volume, respectively, HE staining and TUNEL assay showed that the inhibitory effect of ADM-PLGA-NHAC best group, each group both lung metastasis, and in nude mice by intraperitoneal injection of doxorubicin cardiomyocytes appeared pathological changes, suggesting that we had a cardiac toxicity, and other groups, no significant cardiac abnormalities.Conclusions:1. Our group of chemotherapy drugs nanoscale sustained release capsule and nanoscale hydroxyapatite combined through emulsion evaporation method, freeze drying method developed load ADM-PLGA nanocapsules of nano-hydroxyapatite/ collagen scaffolds in vitro through a series of physical and chemical testing to prove their ability to have a good characterization and inhibition of tumor;2. Through the establishment of a bone defect models and implant materials We were tested Medical Imaging and Histology after 8 weeks and 12 weeks after medical, the results fully confirmed the carrier ADM-PLGA nanocapsules of nano-hydroxyapatite/collagen porous bracket has a good ability to repair bone defects;3. We have established osteosarcoma xenograft model in nude mice after subcutaneous tumor grew to a certain extent by the material we implanted within the tumor, tumor weight by making comparison of the tumor volume and tumor, cardiac histological correlation detection analysis proved that we developed this material and chemotherapy drugs currently in clinical use compared to nude mice having a good anti-tumor effect, and can significantly reduce the toxic side effects. |
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