Use of composite (plaid bone) the basis of chitosan, collagen and hydroxyapatite as a bone substitute in bone defects induced experimentally in iii and IV metacarpal bones of sheep: histological and biomechanical evaluations

• Grant number: 12/23629-9
• Support type: Regular Research Grants
• Duration: November 01, 2013 - October 31, 2015
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal researcher: André Luis do Valle de Zoppa
• Grantee: André Luis do Valle de Zoppa
• Home Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Assoc. researchers: Ana Maria de Guzzi Plepis ; Luciana Corrêa ; Silvia Renata Gaido Cortopassi ; Stefano Carlo Filippo Hagen ; Victor Elias Arana-Chavez ; Virginia da Conceição Amaro Martins

Abstract

In human and veterinary orthopedics, are often required major repairs due to bone loss, either by surgical or pathological origin, and indispensable use of implants for aesthetic and functional correction of members. For years the sheep have been used as experimental models to human studies in orthopedics due to similarity in the weight, bone and joint and bone regeneration. There is a tendency to use the sheep studies also in veterinary medicine, especially in orthopedics equine, being an animal smaller and easier handling, and the number of animals studied may increase, resulting in greater relevance researchers has estatística.Muitos committed to develop and study the compatibility of different types of implants, in order to better promote repair of damaged bony areas. The materials of biological origin, known as biomaterials are being used mainly in the manufacture of prostheses and orthoses. In orthopedics, the use of biomaterials to stimulate osteoinduction and / or osteoconduction in fractures with loss of bone substance still needs to find better ways to use. Natural polymers are generally biodegradable and have excellent biocompatibility compared to synthetic polymers. Chitosan, a natural biomaterial, stimulates cell growth by strong adhesion cells acquire the polymer and proliferate more rapidly. Due to the properties of biocompatibility and biodegradability, this polymer can act as a bone substitute and, over time, be replaced by natural bone. The hydroxyapatite and collagen are also natural biomaterials, being used as natural extracellular matrix, serving as a support for growth of new tissue, for example bone tissue. In this research project will be used twelve ewes not pregnant, are made of a bony defect circular 7 mm in diameter with the aid of a trephine, in every bone III / IV metacarpal (proximal) to those destined to histological examination (Group I) and (on average) for those destined to biomechanical (Group II). Subsequently, on one of the members and random webs are implanted bone base of chitosan, hydroxyapatite and collagen, and the other member will serve as a control. Postoperatively, the animals will be evaluated following the protocol namely lameness, general physical examination, radiographs, ultrasound exams and thermography. After completing 60 days, the sheep for histological assessments (Group I) will undergo new procedure to biopsy bone in the implant area, the fragments collected will be subjected to histological evaluations (optical microscopy and scanning electron microscopy). The sheep intended for biomechanical testing (Group II) will be euthanized to complete 180 days of procedure to collect the bone III / IV metacarpal. The objective of this study is to evaluate the process of tissue repair and behavior webs of chitosan bone, hydroxyapatite and collagen receptor in tissue from experimental bone defects in bone III / IV metacarpal sheep, as well as assessing the biomechanical behavior of the bone substitute . (AU)