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
Seven cases of benign bone tumors, a case of spinal fusion and. seven rases of un-united fractures of shafts of long bones, were treated with a.llogenir bone matrix gelatin (BMG) implants and were followed up for more than one year. All tumor cases were cured by osteo-induction from BMG, while only three of the seven fractures united. Two of the failures were reimplanted with BMG and failed again. Not a single case developed post-operative infection nor immunologic reaction. The BMG used was obtained from the same preparation, so that deterioration of its biological activity by endogenous protease was not likely. BMG small BMG cubes were used in tumor cases and slabs in fractures. The small cubes . were mixed with pieces of gel-foam and parked into the post-operative bony cavities while the slabs were arranged layer by layer at the fracture sites. This might be one of the reasons why the tumor rases had higher rate of cure Another reason was that non-unions needed prolonged, continuous and firm internal and external fixation post-operatively while the tumor cases needed not The amount of BMP calculated from BMG was not enough for early and solid osteogenesis. In the authors'opinion, with the use of new biomaterial, it should be followed by new method of application, but the principles of surgery should not be changed
ABSTRACT
1. 40 cadavers were dissected in order to observe the position, formation and morphology of the osteo-fibrous canal (400 canals) of the posterior rami of the lumbar spinal nerves.2. The average lengths of the osteo-fibrous canals for the posterior ramus of the lumbar nerves in both sexes are: L_1 4.88mm, L_2 4.71 mm, L_3 4.61 mm, L_4 4.57mm, L_5 4.39 mm.3. The average longitudinal diameter of the outlets of the osteo-fibrous canals of the posterior rami of the lumbar nerves in both sexes are: L_1 6.38mm, L_2 6.73 mm, L_3 6.34mm, L_4 5.75mm, L_5 2.61mm.The average transverse diameters of the outlets of the osteo-fibrous canals of the posterior rami of the lumbar nerves in both sexes are: L_1 2.69mm, L_2 2.66mm, L_3 2.68mm, L_4 3.14mm, L_5 2.06mm.4. The shapes of the outlets of the osteo-fibrous canals of the posterior rami of lumbar nerves may be classified into four types: nearly circular 64.75% (259 sides); approximately ellipsoid 30.25% (121 sides); nearly triangular 3.00% (12 sides); nearly oblate 2.00% (8 sides).5. 320 inter-transverse ligaments were observed and measured.6. There was always an iliolumbar ligament interposed between L_5 and S_1.7. Further more, the authors discussed the relationship between the morphology of the nerves and the osteo-fibrous canals in connection with the possible causes of low back pain.