title: Evaluation of the effect of a gamma irradiated DBM-pluronic F127 composite on bone regeneration in Wistar rat.
abstract: Demineralized bone matrix (DBM) is widely used for bone regeneration. Since DBM is prepared in powder form its handling properties are not optimal and limit the clinical use of this material. Various synthetic and biological carriers have been used to enhance the DBM handling. In this study we evaluated the effect of gamma irradiation on the physical-chemical properties of Pluronic and on bone morphogenetic proteins (BMPs) amount in DBM samples. In vivo studies were carried out to investigate the effect on bone regeneration of a gamma irradiated DBM-Pluronic F127 (DBM-PF127) composite implanted in the femur of rats. Gamma irradiation effects (25 kGy) on physical-chemical properties of Pluronic F127 were investigated by rheological and infrared analysis. The BMP-2/BMP-7 amount after DBM irradiation was evaluated by ELISA. Bone regeneration capacity of DBM-PF127 containing 40% (w/w) of DBM was investigated in transcortical holes created in the femoral diaphysis of Wistar rat. Bone porosity, repaired bone volume and tissue organization were evaluated at 15, 30 and 90 days by Micro-CT and histological analysis. The results showed that gamma irradiation did not induce significant modification on physical-chemical properties of Pluronic, while a decrease in BMP-2/BMP-7 amount was evidenced in sterilized DBM. Micro-CT and histological evaluation at day 15 post-implantation revealed an interconnected trabeculae network in medullar cavity and cellular infiltration and vascularization of DBM-PF127 residue. In contrast a large rate of not connected trabeculae was observed in Pluronic filled and unfilled defects. At 30 and 90 days the DBM-PF127 samples shown comparable results in term of density and thickness of the new formed tissue respect to unfilled defect. In conclusion a gamma irradiated DBM-PF127 composite, although it may have undergone a significant decrease in the concentration of BMPs, was able to maintains bone regeneration capability.
authors.affiliation: Institute of Clinical Physiology- CNR, Pisa, Italy.
authors.forename: Tamer
authors.initials: T
authors.lastname: Al Kayal
authors.affiliation: Institute of Clinical Physiology- CNR, Pisa, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Panetta
authors.affiliation: University & IRCCS AOU San Martino-IST, National Institute for Cancer Research, DIMES, Genova, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Canciani
authors.affiliation: Institute of Clinical Physiology- CNR, Pisa, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Losi
authors.affiliation: Institute of Clinical Physiology- CNR, Pisa, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Tripodi
authors.affiliation: CNR/Tuscany "G. Monasterio" Foundation, Pisa Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Burchielli
authors.affiliation: Institute of Clinical Physiology- CNR, Pisa, Italy.
authors.forename: Priscilla
authors.initials: P
authors.lastname: Ottoni
authors.affiliation: Institute of Clinical Physiology- CNR, Pisa, Italy.
authors.forename: Piero Antonio
authors.initials: PA
authors.lastname: Salvadori
authors.affiliation: Institute of Clinical Physiology- CNR, Pisa, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Soldani
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D015415:Biomarkers / Q000378:metabolism; D015519:Bone Density; D001857:Bone Matrix / Q000737:chemistry / Q000502:physiology / Q000528:radiation effects*; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics / Q000378:metabolism; D055419:Bone Morphogenetic Protein 7 / Q000235:genetics / Q000378:metabolism; D001861:Bone Regeneration / Q000502:physiology*; D005269:Femur / Q000293:injuries / Q000601:surgery; D005720:Gamma Rays; D015870:Gene Expression; D006801:Humans; D008297:Male; D020442:Poloxamer / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D055114:X-Ray Microtomography
chemical_list: D001672:Biocompatible Materials; D015415:Biomarkers; C525720:Bmp2 protein, rat; C525821:Bmp7 protein, rat; D055396:Bone Morphogenetic Protein 2; D055419:Bone Morphogenetic Protein 7; D020442:Poloxamer