Volume 4 Issue 4

Authors: To Minh Quan; Doan Nguyen Vu; Nguyen Thi Ngoc My; Tran Le Bao Ha

Abstract: Xenogenic bone grafts have been studied as an alternative to autogenic and allogenic bone grafts in order to satisfy the high demand for orthopedic reconstruction. The aim of the present study was to develop an effective method for xenogenic bone decellularization and cells reseeding forwards bone regeneration applications. Decellularization of porcine cancellous bone blocks with either acetone or chloroform/methanol results in completely acellular bone scaffolds. Umbilical cord blood-derived cells were seeded on the acellular cancellous bone by centrifugal force 2000 rpm in 1 minute and repeated 4 times. After 7 days of in vitro culture, the cells adherence and proliferation within the scaffolds were confirmed by MTT and SEM. In vivo transplantation of acellular bone scaffolds also demonstrated that they did not cause immune response. The achieved results demonstrated that the acellular bone scaffolds are capable of supporting cell adherence and proliferation. Furthermore, in vivo study shows the potential use of acellular bone scaffolds as bone grafts in orthopedic surgery.

Keywords: Xenogenic Bone Graft; Decellularization; Scaffold; Bone Regeneration; Cancellous Bone; Umbilical Cord Blood-Derived Cells; Cell-Seeding


Authors: Islam Nour; Faiza Fattouh; Hala El-Adawi

Abstract: Subcellular fractions of Lactobacillus bulgaricus 761N were investigated for their proteolytic activity that results in production of bioactive peptides in the cell-free supernatant. It was observed that the extracellular extract of L. bulgaricus 761N possessed the highest proteolytic activity of about 63.1 U/ml/min. Consequently, the extracellular fraction was chosen for assessing the proteolytic activity after each step of the optimization process was carried out. The factors of the optimization process involve the incubation period, temperature, pH, salinity (expressed by NaCl concentration), casein content, trace element concentration. The trace elements include cobalt chloride, copper sulphate, calcium chloride and ferrous sulphate. The basal medium used was skim milk agar. The other constituents of the chemically synthesized medium, that would optimize the proteolytic activity that in turn elevate the bioactive peptides production, are determined upon the results of the optimization process. The preferred conditions for maximal activity occurrence was after 48h incubation period, at pH 7, 37 oC, brackish environment at 5gl-1 NaCl content and 5gl-1 casein content. CaCl2 and CoCl2 were found to enhance the proteolytic activity at 1mM, while CuSO4 and FeSO4 were found to be needed in fewer amounts at 0.5mM and 0.1mM, respectively. The antibacterial activity of these bioactive peptides produced in the cell free supernatant was investigated against some human pathogenic bacteria. It was found that it impose a high antibacterial capacity on tested pathogens reaching 89% inhibition.

Keywords: Lactobacillus Bulgaricus 761N; Proteolytic Activity; Chemically Synthesized Medium; Optimization Process; Antibacterial Activity