BMSCs group a2 low density shadow, centrally observable necrosis of femoral head. Magnesium rod group b2 no necrosis, looming magnesium alloy, less obvious low density area as show the arrows. In c1 , c2 , d1 , d2 the femoral head has not collapsed. The density and the shape are nearly normal. Blank control group a2 necrotic collapsed femoral head. Post operation first day: a1 , b1 , c1 , d1. Pre-operation at twelfth week: a2 , b2 , c2 , d2. In the graft, vascular proliferation was observed including some osteoclastic activity. In the alloy area were seen few lamellar necrotic tissue, fine vascular proliferation, and enlarged Haversian canals Fig.
As implant absorption takes place, osteoclast activity was undisrupted. Osteoclasts activity was effective with the presence of the canalicculi. Necrostic cells were significantly decreased. Endosteal proliferation was obvious Fig. Osteoblasts functions were also observed with few new bone formations as seen in the improved femoral head density Figs.
Metaphyseal cancellous bone was normalized, alloy completely disappeared. The bone matrix deposition around the. Though there was obvious slight increase in proximal diaphysis, no histological difference was observed in the alloy area. At twelfth week, although we did not assess the density and level of resilience of the host bone, there was an excellent healing process in the medullary cavity. Identification of osteogenic cells derived from the BMSCs. Twelfth week BMSCs group b with group less giant cells [ black arrow ] and magnesium rod group d both showing irregular bone trabecular arrangement, few new osteoids, hematopoietic hyperplasia.
Blank group h with visible necrotic cells. Osteonecrosis is a disease of unknown pathogenesis that usually progresses to hip joint destruction necessitating total hip arthroplasty. The pathology involves ischemic events followed by death of bone and marrow elements Mont et al. Because the results of hip arthroplasty in patients with osteonecrosis are relatively poor, much focus has been on modalities aimed at femoral head preservation Xiaobing et al. Thus, to succeed in establishing that, the liquid nitrogen technique, easier and convenient, was used in this study because it achieves a high success rate with reliable osteonecrosis and a short pathological process and the basic properties of the bone are maintained Berglund et al.
In this study, the ONFH was properly established with the liquid nitrogen technique used, leading to a collapse of the femoral head in the control group and restoration of the femoral with perfect osteoids formation in the treatment group. The BMSCs derived from rabbits contain a rich source of osteoprogenitor cells, and therefore are an abundant source of seeding cells for tissue engineering. Osteogenic growth factor here bone morphogenetic protein-2 BMP-2 has been demonstrated to facilitate the bone regeneration in a critical size defect model while the in vivo osteogenic differentiation of BMSCs could lead to bone formation under certain conditions Xia et al.
In the environment of high chloride ion and animal body ph 7. In our study, at week 16 after surgery, the magnesium allow was completely absorbed at the implant site. It was reported that, high concentrations of magnesium are toxic, and serum magnesium levels above 1. Magnesium produces a large amount of hydrogen, which can not be absorbed in the body, leading to severe emphysema when the corrosion rate of magnesium is relatively high. Nonetheless, magnesium deficiency is associated with increased contractility of smooth muscle cells and could lead to bronchial smooth muscle contraction or lack of bronchial muscle relaxation de Valk et al.
Contrary to the latter, in this study we found that metaphyseal cancellous bone was normalized and the magnesium alloy accurately measured was nontoxic and was successfully absorbed. The assessment of visceral organs were safe and corrosion resistant. This is further reported in the findings of Vormann As the degradable alloys mainly magnesium and iron based alloys are expected to degrade inside human body, the main compositions of the alloys should be metallic elements that can be metabolized, and demonstrates appropriate degradation rates in the human body Zheng et al.
Toxicity and absorption ability depend on the composition of the alloy. Compared to polymer-based materials, biodegradable metals have higher stiffness and strength, and are more suitable for load bearing conditions Staigera et al. Magnesium is the fourth most abundant cation in the body and the second most common intracellular cation, and it intervenes in calcium transport mechanisms, intracellular phosphorylation reactions.
It constitutes an important determinant of the contraction and relaxation state of bronchial smooth muscle Dominguez et al. So the use of alloy fits better based on its characteristics because, the inclusion of porosity results in a material with reduced yield strength and modulus, corresponding with the lower range of mechanical properties of natural bone Wen et al. The cortical diaphyseal bone diameter was apparently increased but the shape was normal cylindrical and smooth at the sixth week; the twelfth week showed only spongy bone and the increased proximal diaphyseal diameter was maintained.
Although, porous metals were found suitable to be adjustable on demand Wang et al. Therefore, alloying is an essential step to improve mechanical properties and corrosion resistance of magnesium and safe in vivo Zhuang et al. During bone growth and repair, bone formation is initiated and supported by blood vessels. Osteoblasts differentiate and proliferate around the vessel, arrange along the vascular endothelium and then excrete osteoids in a direction away from the vessel.
When the osteoblasts mature and develop into osteocytes, the newly formed bones deposit around the vessel Huang et al.
Chinese Optics Letters
Bone is a complex tissue that continually undergoes dynamic biological remodelling, i. We believe that magnesium alloy and BMScs-BMP-2 are promising easy materials which may require a weekly assessment in other experimental animals but for a long time study period to clear all bias on the toxicity of magnesium and its ally with BMP-2 is promising for repair of the ONFH. It will be safer and more excellent to evaluate the magnesium and it alloys in vivo than in vitro due to the toxicity effect reported by few authors.
No any obvious complication nor damage was found over the investigated viscerals: liver, lung, kidney. Thomas, USA, January, Etienne, France, May Pacific Rim Ceramics Conference, Symp. Gordon Research Conference on Physical Metallurgy, International Conference on Superplasticity, Grenoble, France, Wu, P. Wilkinson, D.
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Nemcko, M. Allow All Cookies. Chinese Optics Letters Vol. SS Not Accessible Your account may give you access. Abstract The energy storage of solar radiation with magnesium as an energy reservoir is proposed for renewable energy cycle. References You do not have subscription access to this journal. Cited By You do not have subscription access to this journal. Please login to set citation alerts.
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