Microscopic analisys of porous microgranular bovine anorganic bone implanted in rat subcutaneous tissue

Abstract

The tissue response to porous bovine anorganic bone implanted in rat connective tissue was evaluated by subjective light microscopy analysis. Forty rats were divided into two groups: control (empty collagen capsules) and test (collagen capsule filled with 0.1g biomaterial) and killed 10, 20, 30 and 60 days after implantation. At 10 days, intense chronic inflammatory infiltrate consisting mainly of macrophages and inflammatory multinucleated giant cells (IMGC) was observed. Neutrophils, plasma cells and lymphocytes were present in discrete amounts and slowly disappeared along the repair process. Porosity of the material was filled by reaction connective tissue exhibiting IMGC. The fibrosis was more intense after 60 days and clearly higher than the control group. Thus, the material did not cause any severe adverse reactions and did not stimulate the immune system. Based on the results it could be concluded that deproteinized bovine cancelous bone was well tolerated by rat connective tissue.

Alveolar bone regeneration in rats after grafting of anorganic bovine bone and thick synthetic bioceramic

“…20 All groups showed intense fibroblastic proliferation within 7 days, which declined after 15 days and could be explained by the organization and maturation of the connective tissue. 27,28 This result differs from the findings of another study 22 in which only a few cells were observed in the central area of the granulation tissue within the first days. Nevertheless, the authors explained that this probably occurred due to the large amount of compacted material used, which may have retarded the penetration of connective tissue cells and blood vessels.…”

“…21,29 Additionally, distribution of graft particle sizes can play an important role in the emergence of new blood vessels, particularly because if there is wide size variation, the smaller particles tend to obstruct the spaces among the large particles, thus reducing vascularization and also cell penetration. 16,22 Analysis of results reveals that although both types of grafting material are microgranular, with particle sizes ranging from 0.25 to 1 mm, this variation was not so great as to prevent the formation of blood vessels and cell migration.…”

“…20,21,22 In the 15-day period, the inflammatory infiltrate appeared Groups Inflammatory infiltrate Fibroblast density Angioblastic density Bone neoformation T07 T15 T30 T07 T15 T30 T07 T15 T30 T07 T15 discreet such as in GI. This reduction is based on an initial aggressive reaction to a foreign body, which is later on attenuated due to the biocompatibility of the graft, 11,15,22,23 which may be attributed to the fact that both bone substitutes are composed of hydroxyapatite similar to the crystalline phase of natural bone. 24 It was also found that the presence of biomaterial inside the socket did not delay the healing process, thereby agreeing with the results of previous studies.…”

“…33,35 Porosity also favors the resorption process of material. 22,35 In fact, an optimal synthetic bone substitute should be reabsorbed and replaced by new bone, since the longterm presence of material can limit bone formation and affect healing. 11,35,36 Nevertheless, none of the GII and GIII specimens showed signs of grafting particle reabsorption within the studied periods, thereby agreeing with other authors who proposed that some Ca/P-derived material has slow resorption and require several months to complete the process.…”

Avaliação da biocompatibilidade da hidroxiapatita nanoparticulada no subcutâneo de ratos

“…Pescinini et al (1996), em estudo semelhante, também observaram em 7 dias resposta inflamatória, mas sem a presença de necrose. Zambuzzi (2005) utilizando osso bovino no subcutâneo de ratos mostrou que nos 10 primeiros dias, …”