A B S T R A C TMagnesium (Mg)-based biometal attracts clinical applications due to its biodegradability and beneficial biological effects on tissue regeneration, especially in orthopaedics, yet the underlying anabolic mechanisms in relevant clinical disorders are lacking. The present study investigated the effect of magnesium (Mg) and vitamin C (VC) supplementation for preventing steroid-associated osteonecrosis (SAON) in a rat experimental model. In SAON rats, 50 mg/kg Mg, or 100 mg/kg VC, or combination, or water control was orally supplemented daily for 2 or 6 weeks respectively. Osteonecrosis was evaluated by histology. Serum Mg, VC, and bone turnover markers were measured. Microfil-perfused samples prepared for angiography and trabecular architecture were evaluated by micro-CT. Primary bone marrow cells were isolated from each group to evaluate their potentials in osteoblastogenesis and osteoclastogenesis. The mechanisms were tested in vitro. Histological evaluation showed SAON lesions in steroid treated groups. Mg and VC supplementation synergistically reduced the apoptosis of osteocytes and osteoclast number, and increased osteoblast surface. VC supplementation significantly increased the bone formation marker PINP, and the combination significantly decreased the bone resorption marker CTX. TNFα expression and oxidative injury were decreased in bone marrow in Mg/VC/combination group. Mg significantly increased the blood perfusion in proximal tibia and decreased the leakage particles in distal tibia 2 weeks after SAON induction. VC significantly elevated the osteoblast differentiation potential of marrow cells and improved the trabecular architecture. The combination supplementation significantly inhibited osteoclast differentiation potential of marrow cells. In vitro study showed promoting osteoblast differentiation effect of VC, and antiinflammation and promoting angiogenesis effect of Mg with underlying mechanisms. Mg and VC supplementation could synergistically alleviate SAON in rats, indicating great translational potentials of metallic minerals for preventing SAON.

Smart gels have many applications in sensors, actuators, shape memory intelligent devices, recognition, self-healing, drug release, biomimetic soft robot design, biomimetic tactile, neural regeneration, biomimetic membranes, supercapacitor, dye-sensitized solar cells, advanced lithium polymer batteries, environmental fields, biomedical fields, et al. And that cyclodextrins are one of the typical macrocycles with good recognition ability, and endowed with fascinating hydrophobic cavities and hydrophilic surface, which enable the encapsulation of diverse small organic molecules by forming inclusion complexes. In this paper, grafted copolymerization between acrylic acid and N,N-dimethyl acrylamide in the presence of water-soluble cyclodextrins was carried out. The effect of ratio of copolymerization monomer on the grafted polymer was examined. The results indicated that self-crosslinking smart gel with multi-stimuli responsive was obtained by selecting suitable the ratio of copolymerization monomer, its behaviors of swelling/shrinking were examined. The adsorption properties and releasing characteristics of smart gel were performed with simulating drugs. Some meaningful results were obtained. These series grafted copolymer would also be used to modify the surface and interface properties of low-dimensional functional materials or heterostructured nanocomposites for intelligent organic-inorganic functional nanocomposites, some good results were obtained.