ABSTRACT
Bone allograft is widely used to treat large bone defects or complex fractures. However, processing methods can significantly compromise allograft osteogenic activity. Adjuvants that can restore the osteogenic activity of processed allograft should improve clinical outcomes. In this study, zinc was tested as an adjuvant to increase the osteogenic activity of human allograft in a Rag2 null rat femoral defect model. Femoral defects were treated with human demineralized bone matrix (DBM) mixed with carboxy methyl cellulose containing ZnCl2 (0, 75, 150, 300 µg) or Zn stearate (347 µg). Rat femur defects treated with DBM-ZnCl2 (75 µg) and DBM-Zn stearate (347 µg) showed increased calcified tissue in the defect site compared to DBM alone. Radiograph scoring and µCT (microcomputed tomography) analysis showed an increased amount of bone formation at the defects treated with DBM-Zn stearate. Use of zinc as an adjuvant was also tested using human cancellous bone chips. The bone chips were soaked in ZnCl2 solutions before being added to defect sites. Zn adsorbed onto the chips in a time- and concentration-dependent manner. Rat femur defects treated with Zn-bound bone chips had more new bone in the defects based on µCT and histomorphometric analyses. The results indicate that zinc supplementation of human bone allograft improves allograft osteogenic activity in the rat femur defect model.
Subject(s)
Allografts/immunology , Cancellous Bone/cytology , Osteogenesis/physiology , Zinc/metabolism , Animals , Bone Matrix/transplantation , Bone Transplantation/methods , Cancellous Bone/immunology , Femur/metabolism , Humans , Rats , Transplantation, Homologous/methodsABSTRACT
Milk contains various bioactive components with osteoanabolic properties. This study investigates the comparative effect of the whey-derived antioxidative (YVEEL) and angiotensin-converting enzyme inhibitory (YLLF) bioactive peptides on bone remodelling in ovariectomised (OVX) osteoporotic rat model. OVX animals were administered with antioxidative (AO) (500 µg kg-1 day-1) and angiotensin-converting enzyme inhibitory (ACE inhibitory) (50 µg kg-1 day-1) peptides for eight weeks. Trabecular microarchitectural parameters of femoral and tibiae bone were determined using micro-CT scan. Bone formation, resorption, turnover markers (ALP, RANKL, OCN) and inflammatory cytokines (TNF-α, TGF-ß, IFN-γ) were determined by ELISA. Both AO and ACE inhibitory peptides inhibited the increase in bone turnover and inflammatory cytokines while increased the bone formation markers. The altered morphometric parameters of femoral and tibiae bones due to OVX were strikingly attenuated by the peptide administration. The results indicated that AO peptide exerts more osteoprotective potential than ACE inhibitory peptide by suppressing inflammatory status and enhancing bone formation markers.