Use of chitosan and βtricalcium phosphate alone

Authors: A S Azevedo M J C Sá M V L Fook P I Nóbrega Neto O B Sousa S S Azevedo M W Teixeira F S Costa A L Araújo

Publish Date: 2013/11/17

Volume: 25, Issue: 2, Pages: 481-486

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Abstract

The aim of this research was to evaluate the process of bone regeneration in rabbits using chitosan and betatricalcium phosphate βTCP independently and in combination A total of 12 New Zealand rabbits of both sexes with average weight of 30 ± 057 kg were used Animals were randomly divided into two experimental time points with six animals euthanized 45 days after surgery and six euthanized 90 days after surgery We performed two osteotomies in each tibia The left tibia was used for the chitosan QUI and control groups and the right tibia was used for the βTCP alone and in combination with chitosan QUI+TCP groups Tomographic evaluation showed no statistically significant difference among groups however radiopacity was higher in the treated groups Comparative descriptive histological evaluation found that treatment groups stimulated a more pronounced tissue repair reaction and accelerated bone repair Morphometric analysis showed that treatment groups presented statistically higher bone formation compared with the control groupThe use of biomaterials in orthopedic surgery is becoming routine allowing for greater option in cases requiring an adjuvant for the process of bone repair Among the list of biomaterials calcium phosphates are widely studied and used in dentistry and bone surgery 1 2 Betatricalcium phosphate βTCP compared with hydroxyapatite is more osteoconductive with excellent biodegradation properties characterized by rapid absorption and replacement by new bone matrix 3 4 Several studies investigating biopolymers highlight the successful use of chitosan due to its ability to stimulate bone induction thus favoring faster repair 5 This can be explained by the unique surface property of chitosan which stimulates macrophage receptors thus promote the release of growth factors maximizing the osteogenic process 6 7 8 Several combinations of biomaterials have been studied to accelerate and maximize the regeneration of bone tissue 9 The combination of chitosan with βTCP provides an alternative reparative process for bone tissue This composite provides not only a stimulus for bone induction from chitosan but also osteoconductivity from the βTCP mineral thereby favoring increased formation of bone matrix by osteoblasts as supported by previous studies 5 10In this experiment 12 New Zealand adult rabbits mean weight 30 ± 057 kg of both sexes were used The animals were randomly divided into two experimental time points with six animals in each time group according to the period of euthanasia 45 or 90 days after surgery Animals were placed in individual cages dewormed with albendazole 5  IbazoleIBASA by giving 20 mg/kg orally and passed through an adjustment period of 7 days before the start of the experiment Animals received balanced rations twice a day and were given drinking water ad libitum throughout the experimentThe implants used in this study were provided by the Biomaterials Group Department of Materials Engineering at the UFCG For preparation of the sponge implants chitosan SigmaAldrich Brazil 448877 molecular weight 190 × 105–310 × 105 g/mol deacetylation degree 75–85  glacial acetic acid Vetec Brazil and genipin SigmaAldrich Brazil 6902778 molecular weight 22623 g/mol purity ≥98  HPLC were used For further processing of scaffolds absolute ethanol 995  GL Nuclear Brazil hydrated alcohol 70  INPM TUPI Brazil and sodium hydroxide Vetec Brazil were usedFor the synthesis and characterization of βTCP the method of precipitation by wetting involving a neutralization reaction between phosphoric acid solution H3PO4 and calcium hydroxide CaOH2 was used The stoichiometric amounts of the solutions were determined according to the value of the atomic ratio between the calcium and phosphorus atoms from calcium phosphate Powder CaOH2 was added to deionized water and vigorously agitated and heated to 80 °C To this solution H3PO4 was slowly added under constant agitation After thorough mixing of the two reactants the temperature was raised to 100 °C and agitation was continued until viscosity was reached The ceramic paste obtained was dried at 110 °C for 24 h and the product was deagglomerated passed through a 200 mesh sieve to obtain the powder heattreated at 20 °C per minute and held at 1100 °C for 2 hAfter shaving a preanesthesia medication of acepromazine Acepran 1  VETNIL Brazil 1 mg/kg was given intravenously IV and then anesthesia medication comprising tiletamine associated with zolazepam Zoletil 100 VIRBAC Brazil was given at a dose of 15 mg/kg IV We also performed epidural anesthesia with 2  lidocaine anesthetic BRAVET BRAVET Brazil at a dose of 022 mL/kg associated with tramadol TramalPFIZER Brazil at a dose of 1 mg/kg After antisepsis of the operative area with a solution of chlorhexidine 05  05  Riohex RIOQUÍMICA Brazil a skin incision was made along the medial margin of the tibial crest and dilatation of the subcutaneous tissue and muscle was carried out Longitudinal resection of the periosteum was performed and two holes were constructed one in the proximal metaphysis and another at the distal metaphysis using a surgical drill with a 30mm diameter for implant placement Treatments were as follows in the left tibia control group C osteotomy was performed but not completed for any implant in the proximal metaphysis and chitosan group QUI with 85  deacetylation on the distal metaphysic and in the right tibia the βTCP group TCP in the proximal metaphysis was introduced at a Ca/P ratio of 15 and the βTCP combined with chitosan group QUI+TCP on the distal metaphysis All implants were autoclaved prior to use Synthesis was performed in the tissues This procedure was performed in both limbs

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