ABSTRACT
Objective:To analyze the effects of a novel type of polydopamine (PDA)-coated porous titanium alloy scaffolds loaded with zoledronic acid-gelatin nanoparticles (ZOL-GNPs) for topical sustained drug release on osteoclasts in vitro. Methods:After porous titanium alloy scaffolds were fabricated using electron beam melting technique and ZOL-GNPs with different ZOL concentrations (0, 1, 10, 50, 100, 500 μmol/L) were prepared by desolvation method, PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs were constructed by combining the two. The characteristics of the scaffolds were analyzed. The biomechanics of 3 different scaffolds (bare porous titanium alloy scaffolds, PDA-coated porous titanium alloy scaffolds, and PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs) were investigated. Drug release detection was carried out by high performance liquid chromatography on the 1st, 4th, 7th, 14th, 21st, and 28th days respectively. The osteoclasts were inoculated into the novel scaffolds with different ZOL concentrations. The expression of osteoclast-related genes was detected by real-time quantitative (RT)-polymerase chain reaction (PCR); the expression of osteoclast-related proteins was detected by Western-blot.Results:The PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs were successfully constructed. Electron microscope scanning showed that the GNPs were well spheroidized, smooth in surface, and uniformly dispersed, with a particle size of (243.6±63.4) nm. The ZOL-GNPs were uniformly compounded on the surface and in the pores of the scaffolds, and the spheres were regular in shape with no adhesion. The biomechanical experiments showed that the elastic moduli of the porous titanium alloy scaffolds under 3 different conditions were (1.81±0.12) GPa, (1.80±0.23) GPa and (1.81±0.15) GPa, showing no significant difference ( P> 0.05). The drug release percentage in the porous titanium alloy scaffolds was obviously high on the first day, and increased gradually and slowly in the subsequent 27 days. In the scaffolds with a low concentration ZOL, more osteoclasts adhered and proliferated; in the 50 μmol/L scaffolds, spheroid cells appeared; the spheroid cells increased and even apoptosis occurred with an increase in the ZOL concentration. RT-PCR showed that the expression of Ctsk gene and TRAP gene increased with the increased ZOL concentration, peaked in the 50 μmol/L scaffolds, and then decreased with the increased concentration, showing statistically significant differences ( P < 0.05). Western-blot showed that the expression pattern of Ctsk and TRAP was similar to that of their related genes. Conclusions:The novel PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs demonstrate good mechanical properties and an anti-osteoporosis effect via their topical sustained drug release. The scaffolds with a ZOL concentration of 50 μmol/L may exert the best effect on inhibition of osteoclasts.
ABSTRACT
BACKGROUND:Infection is the catastrophic complication after total hip arthroplasty, moreover, its diagnostic criteria has not been unified, and treatment options were also controversial. The removal of the focus of infection was complete or not determines whether the joint could be reconstructed and the joint function could be restored. OBJECTIVE:To analyze the experience and efficacy of thorough debridement in two-stage revision surgery for treatment of infection after hip arthroplasty. METHODS:Total y 23 (24 hips) patients with infection after hip arthroplasty were treated at the Department of Orthopedics, Nanjing General Hospital of Nanjing Military Area Command of PLA from August 2008 to January 2013. The diagnostic criteria were in line with consensus. The repair options defined as two phrases:the first phrase was thorough debridement plus antibiotic-containing bone cement implanted with intervals;the second phrase was joint reconstruction. If the infection persisted in interval, debridement could be repeated, and then underwent joint reconstruction after the thorough control of infection. Harris scores of hip function were determined after revision during fol ow-up. Infection control condition was evaluated. RESULTS AND CONCLUSION:Al the patients were fol owed up, ranged from 1 to 5 years. The Harris scores increased from an average of 36.5 (27-45 scores) before treatment to an average of 88.6 (76-98 scores) after treatment. There was no infection recurrence. Infection control rates reached to 100%. These results suggest that two-stage revision is an effective method for treatment of infection after total hip arthroplasty. Thorough debridement plays a crucial role, and it can effectively control infection recurrence, improve prosthesis stability, so as to reconstruct joint function.
ABSTRACT
Objective:To obtain apoptin gene and to induce tumor cell (HeLa) apoptosis. Methods:Apoptin gene was amplified by PCR from CAV TK5803 genomic DNA,and was then cloned into pCDNA3.1/His/Topo vector. After confirming by DNA sequencing, apoptin gene was subcloned into pCIneo vector.Recombinant plasmid pCDNA3.1/His/Topo-apoptin and pCIneo-apoptin were transformed into HeLa cells by Lipofectamine reagent. Three days after transfection,the HeLa cell was stained by Honchest 33258 and apoptosis was analysed by fluorescence microscope. Results and Conclusions: The full-length apoptin gene was cloned by PCR and inserted into pCDNA3.1/His/Topo vector. Sequence analysis demonstrated that it was same as published apoptin gene sequence. Three days after transfection, HeLa cell turned into apoptosis.