Evaluation of bacterial celulose composites with addition of growth factor regulatory peptide in the bone regeneration

Abstract

In recent years, biotechnology has greatly advanced in the development of biomaterials such as resorbable or nonresorbable membranes. They present enormous potential application in various and complex situations that require accurate and balanced support to restore/supplement cell or tissues proliferation necessities, such as bone tissue regeneration. The ideal would be developing materials which also induced osteogenesis, were biocompatible, readily available in the market and low cost. The Chemistry Institute (IQ) of the São Paulo State University in Araraquara (UNESP) developed from bacterial cellulose (BC) composites with hydroxyapatite (HA) that improve bone regeneration. Bacterial cellulose is a biopolymer that can be combined with other components forming new composites for different applications in tissue repair. When BC is associated with hydroxyapatite (HA) it forms a composite (CB-HA) that shows both bioactive and osteoconduction potentials, giving positive contribution in bone regeneration. The BC-HA was also adsorbed with the regulatory peptide growth factor pentapeptide OGP [10-14], and this composite showed an improved osteogenic effect both in vitro and in vivo. Besides the complete chemical characterization of the mentioned composites, very promising results were obtained from these biochemical and histological assessment when used for bone regeneration after non-critical defect in the femur of rats. This study aims to evaluate: i) the potential of BC composites associated with OGP in the process of bone regeneration after critical defect in mice calvaria, ii) the participation of gene expression in this process, and iii) the resorption time of the BC membrane added with Cellulase, since the cellulase degrades BC matrix. 330 animals will be utilized, randomly distributed in five groups. Group I: BC-HA; Group II: BC-HA-OGP; Group III: BC-HA-OGP [10-14]; Group IV: CB-cellulase and Group V: no BC membrane (control). The newly formed tissues will be evaluated by microscopic analysis (H & E, Masson trichrome), stereometric analysis, gene expression and protein expression analysis of VEGF (vascular endothelial growth factor) by ELISA immunoassay. The results will be statistically analyzed by parametric or non-parametric tests depending on the adherence of the data to the curve of normality. All tests will be performed at a significance level of 5% using the SAS and BioEstat v.5.0 software. This study is expected to indicate what biomaterial has better behavior in bone regeneration and how is the participation of gene expression in this process. The expansion of knowledge of the biological potential of biomaterials developed in IQ will contribute to their future use in the medical device industry. (AU)