Papers by Keyword: In Vivo

Abstract: The aim of this study was to evaluate the interaction of bioactive and biodegradable poly (lactide-co-glycolide)/bioactive glass (PBG) nanocomposite coating with bone and human adipose-derived stem cells (hASC) in vivo and in vitro, respectively. Sol-gel derived 58S bioactive glass (BG) nanoparticles and 50/50wt% poly (lactic acid)/poly (glycolic acid) (PLGA) were used to prepare the coating. The nanocomposite coating was characterized by SEM, XRD, and AFM. Mechanical stability of the prepared nanocomposite coating was studied during intramed­ullary implantation of coated Kirschner wires (k-wires) into rabbit tibiae. Titanium mini-screws coated with PBG nanocompoite coating was implanted intramedullary in rabbit tibia. Bone tissue interaction with the prapared nanocomposite coating was evaluated 30 and 60 days after surgery. The effect of PBG nanocomposite coating on the attachment and viability of human adipose-derived stem cells (hASCs) was investigated. Results showed that PBG nanocomposite coating remained stable on the K-wires with a minimum of 96% of the original coating mass. Tissue around the coated implants showed no adverse reactions to the coating. Woven and trabecular bone formation were observed around the coated samples with a minimum inflammatory reaction. The hASCs showed excellent attachment and viability on the PBG nanocomposite coating. It was concluded that PBG nanocomposite coating provides an ideal surface for bone formation and stem cells attachment and it could be used as a candidate for coating the dental and orthopedic implants.

Abstract: Nanoparticles (NPs) are used in various forms in consumer products including, cosmetics, food packaging, textiles and also in air and water cleaning, production of electro chromic windows, or smart windows and gas sensors. Many NPs have also been evaluated for potential use in biomedical applications as efficient delivery carriers for cancer diagnosis and therapy. Nowadays, NPs are being developed to create fascinating nanotechnology products. To develop NPs for broad applications, potential risks to human health and the environment should be evaluated and taken into consideration. Again, to translate these nanomaterials to the clinic and industrial domains, their biosafety needs to be verified, particularly in terms of genotoxic and carcinogenic effects. To evaluate evidenced-based practices for NPs safety, we performed a systematic review of the published English-language literature. We performed a systematic keyword search of PubMed for original research articles pertaining to reports on assessment of risks due to carcinogenic and mutagenic effects by different NPs. We identified 362 original articles available for analysis. The included studies were published between 1993 and 2012. The in vivo or in vitro genotoxicity studies were performed on only 18 out of 148 kinds of NPs in industry today. Likewise, the carcinogenicity investigations were performed on only 14 out of 148 NPs. The 10 types of the NPs including some titanium, aluminium, carbon black and silver molecules were found to have both mutagenic and carcinogenic potential. The important finding was also that there is a lack of systematic assessment of the DNA damaging and carcinogenic potential of NPs in spite of their extensive use in nanotechnological applications.

Abstract: Tungsten (VI) oxide particles (WO₃, <100 nm particle size) are used for many purposes including production of electro chromic windows, or smart windows, x-ray screen phosphors and gas sensors in everyday life. However, the carcinogenic and genotoxic potential of this nanomaterial have not been sufficiently evaluated. Therefore, the genotoxic potential of WO₃ was examined in Sprague-Dawley rat bone marrow cells by using mitotic index (MI), micronucleus (MN) and chromosome aberrations (CA) assays. Rats were orally gavaged with a single dose of WO₃ (0, 25, 50 and 100 mg/kg) for 30 days. All WO₃ treatments significantly decreased MI rates as compared to the control group. No increase in the incidence of CA was observed at any WO₃ nanoparticle dose in the CA test although MN formation was significantly (P<0.05) increased for 50 and 100 mg/kg doses. The observed alterations in MN and MI parameters reveal that WO₃ has cytotoxic and genotoxic potential and could pose environmental and human health risk.

Abstract: Textile vascular prostheses ARTECOR were coated by laser with amorphous diamond-like carbon layers (DLC) with thickness up to 200 nm. Layers were created in 0.25 Pa of Argon at laser energy density of 8 or 22 Jcm-2. Depending on the deposition conditions, DLC properties moved from soft „graphitic“ to more „diamond“ (53 % of sp3 bonds). Coated prostheses of various DLC thickness and sp3 content were implanted into carotid artery of Merino sheep. The prostheses were extirpated after 100 days (~180 days). From preliminary results follows that prostheses coated with DLC layer thickness of 20 nm and higher sp3 content showed the best results.

Abstract: Many efforts in these last years have dedicated in the development of new drugs due to an increase of microbial organisms resistant to multiple antibiotics, and silver nanoparticles appears as a novel antimicrobial agent. The aim of our work was to evaluate the in vitro and in vivo antileishmanial activity of the silver nanoparticles prepared by chemical process and by biosynthesis from Fusarium oxysporum. In vitro antipromastigote activity of L. amazonensis showed that silver nanoparticles chemically synthesized (AgCHEM), biogenic silver nanoparticles (AgBIO) and amphotericin B decreased the parasite load up to 13%, 61%, and 68%, respectively. The IC₅₀ of AgCHEM and AgBIO was 103.5 ± 11.5 μM and 31.6 ± 8.2 μM respectively. The assay of antileishmanial effect of these nanoparticles was evaluated in vivo (BALB/c mice) against L. amazonensis. The mice infected with promastigotes of L. amazonensis in the ear showed that after 10 days of treatment (twice a week for four weeks) the wound in the control (mice treated with PBS solution) was large, while the wound of the mice treated with amphotericin B (positive control) exhibited low size of lesion. The same parasitemia inhibition with amphotericin B was observed when AgBIO were used at 300 fold lower concentration, and 100 fold less concentration of AgCHEM than amphotericin B. Thus, these nanoparticles can be used in wound helping like cutaneous leishmaniasis.

Abstract: Periodontitis is one of the most common inflammatory diseases, which can lead to early tooth loss. The conventional treatment of periodontitis is to arrest the disease progression. Most reconstructive procedures involve application of bone substitutes, barrier membranes or a combination of both into the bony defects. Calcium phosphate cements (CPCs) are the predominant type of bone substitute material used for reasons of injectability and hence perfect filling potential for bone defects. Recently, injectable apatitic CPCs demonstrated to be more rapidly degradable when combined with poly (lactic-co-glycolic) acid (PLGA) microspheres. Further, PLGA microspheres can be used as a delivery vehicle for growth factors. In this study, the performance of injectable CPCs as a bone substitute material for alveolar bone defects created in Beagle dogs was evaluated. Four CPC-formulations were generated by incorporating hollow or dense PLGA microspheres, either or not loaded with the growth factors (platelet derived growth factor (PDGF) and insulin-like growth factor (IGF). Implantation period was 8 weeks. Bone formation was based on histological and histomorphometrical evaluation. The results demonstrated that filling alveolar bone defects with CPC-dense PLGA revealed significant more bone formation compared to CPC-hollow PLGA either or not loaded with IGF and PDGF. In summary, we conclude that injectable CPC-dense PLGA composites proved to be the most suitable material for a potential use as off the shelf material due to its good biocompatibility, enhanced degradability and subsequent bone formation.

Abstract: While nano-hydroxyapatite (nano-HAP) has been well known for series of amazing properties in chemical or physical, the controversy on the risks of its applications has also been existed. The worries of nano-HAP applications in preclinic and clinic indicate the blank researches of nano-HAP pharmacodynamics. It is important and necessary to trace and clarify the localizations of HAP nanoparticles in vivo. In the present paper, 18F is used as radiotracer for Positron Emission Tomography (PET) imaging of HAP nanoparticles. Through the transverse plane slices and three-dimensional reconstruction pictures, it is very clear to observe the localization of nano-HAP in vivo at real time. Most nano-HAP particles were noted in organs lump, liver, spleen, stomach and existed for period of time. Therefore, PET can be a new powerful technique for tracing nano-biomaterial and their pharmacodynamics researches.

Abstract: The objective of this study was to investigate the in vitro and in vivo biological responses to carbonate apatite (cHA) in comparison to hydroxyapatite (HA). Spheres (400<ø>500 μm) of both materials were synthesized under 5°C (cHA) and 90°C (HA) and not sintered. The in vitro cytocompatibility was determined by the XTT assay, according to ISO 10993-5:2009, after exposure of MC3T3-E1 cells to the materials extracts. Ethics Commission on Teaching and Research in Animals approved this project (CEPA/NAL 193/10) and, subsequently, the biomaterials were grafted in the subcutaneous tissues of mice (n=15). After 1 and 3 weeks, five animals of each group were killed for samples removal containing biomaterials and surrounding tissues for histological examination. Semi-serial (5-μm thick) sections were cut and stained with Hematoxylin and Eosin (HE) and the presence of inflammatory infiltrates and biomaterials resorption were evaluated. The experimental group of 3 weeks didn’t show the presence of spheres of both biomaterials and few spheres were observed after 1 week. Histological analysis showed the granulation tissue around the biomaterials with the presence of multinucleated giant cells. After 3 weeks it was observed the presence of fibrous tissue around biomaterials and few inflammatory cells. No signals of tissue necrosis were observed in both groups in all experimental studied periods. Nanostructured carbonate apatite spheres are cytocompatible, biocompatible and present initial biosorption on the subcutaneous comparable to stoichiometric HA, indicating its suitability for further studies on regenerative medicine.

Abstract: This study investigated the osteoinductive potential of granules of stoichiometric hydroxyapatite (HA) and 0.5% zinc containing hydroxyapatite (ZnHA) in intramuscular (IM) site of rabbit’s abdomen. The biomaterials were both used in granular form, with 75% porosity and particle diameter between 450 and 500μm, sintered at 1100°C. Both materials performed adequately on a multiparametric in vitro cytocompatibility assay, indicating their suitability for in vivo testing. After approval by the Ethics Commission on Teaching and Research in Animals, fifteen rabbits were submitted to general anesthesia, incision and tissue dilatation, and a small site was created for HA (right incision) and ZnHA (left incision) intramuscular implantation. The animals were killed after 2, 4 and 12 weeks for biomaterials and surrounding tissues removal. Histological analysis after 2 weeks revealed the presence of granulation tissue surrounding biomaterials with multinucleated giant cells and no newly formed bone for both materials. After 4 weeks there was fibrous tissue involving the material and few inflammatory cells. Following 12 weeks it was observed the presence of connective tissue surrounding the biomaterial, cellularized enough for the two experimental groups, but it was not observed the presence of bone matrix associated with the biomaterials. We conclude that both biomaterials are cytocompatible and did not present the property of osseoinduction after 12 weeks of implantation.

Abstract: Clinoptilolite mineral which is a member of zeolite family has been recently used in medical and dental applications. Until today, it has never been used as a graft material. In the present study tricalcium phosphate (TCP) imbued 90-95% pure clinoptilolite was used as graft in rabbit tibia. General anesthesia was accomplished using intra muscular (IM) injections of Xylazin and Ketamine HCL. TCP imbued clinoptilolite was placed in the defects created in the tibias of the subjects. Control group defects were left empty. One group was sacrificed on day 28 and the other group on day 56 to evaluate osteogenesis, residual graft material, inflammation and fibrosis. Histological evaluation revealed new bone formation at 28 days to be 14/7 at control group where as its 11/7 for the experimental graft group. At 56 days the values are as 18/7 for control and 14/7 for the experimental graft groups (n = 7). Our study group is the first to perform intrabony application of clinoptilolite. No evidence of abnormal inflammatory cell formation or fibrosis was witnessed in groups. When TCP, which can be used as a standalone graft material, was mixed with zeolite it was not as effective as expected. We believe that, TCP particles are absorbed and captivated in the initial phase and due to absorption strength of zeolite cannot be released back to the environment. We assume its effect can increase with longer time periods. Bone formation without infection is observed around graft particles. Based on the present study, since clinoptilolite does not provoke an inflammatory process, its use in unison with TCP can provide a supporting structure in defects.