Evaluation of angiogenesis in xenografts collected from bovine bones implanted at intracorporeal sites of rabbits (Oryctolagus cuniculus) as an in-vivo bioreactor model

Author(s)

Gabriel Luiz Montanhim

• Document type: Master's Dissertation
• Press: Jaboticabal. 2019-04-25.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2019-02-25
• Advisor: Paola Castro Moraes; Luis Gustavo Gosuen Gonçalvez Dias

Abstract

There is increasing demand for natural or synthetic materials that aid in the formation of new bone tissue. For this, the use of grafts for correction of bone failures, for example, gains more and more prominence. The aim of this study was to evaluate the neovascularization and subsequent osteinduction of bovine xenografts implanted in intracorporeal sites of rabbits, considered as bioreactor. To do this, 30 rabbits were distributed in six groups, according to the evaluation time (seven, 15, 30, 45 and 60 days) in which each animal received three different intracorporeal sites (A1 - omentum pouch; intermuscular of the femoral quadriceps, A3 - subperiosteal of the ilium bone), the xenogenes implants. The evaluations were made with macroscopic and histopathological analyzes, quantifying inflammatory cells, neoformed bone tissue, presence of giant cells and neoangiogenesis. Histopathological analyzes showed intense neoangiogenesis in all implants, presence of inflammatory infiltrate and giant cells at the A1 site and presence of bone neoformation at the A3 site. At the same time it can be noticed degeneration of the implants and formation of fibrous capsule. Statistical analyzes in the comparison of site interaction with the days of analysis showed no significant difference (p ≤ 0.05) at any time of neovascularization analysis and showed a significant difference (p ≥ 0.05) in the other comparisons. The omentum is a richly vascularized organ containing in its structure inflammatory cells and endothelial growth factors, which justifies being the place that one can observe the greater presence of neovasal and inflammatory cells. The periosteum has in its innermost layer osteoblastic precursors, thus favoring the formation of new bone tissue from the moment the implant was revascularized. By containing antigenic particles the body recognized the xenograft implanted as a foreign body, initiating an aseptic foreign body reaction, which evolved to degenerate parts of the biomaterial. (AU)

• FAPESP's process: 17/04142-5 - Evaluation of angiogenesis in xenografts collected from bovine bone implanted at intracorporeal sites of rabbits (Oryctolagus cuniculus) as an in vivo model of bioreactor
• Grantee: Gabriel Luiz Montanhim
• Support Opportunities: Scholarships in Brazil - Master