Vertebral plate regeneration induced by radiation-sterilized allogeneic bone sheets in sheep / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To evaluate the effects and mechanism of radiation-sterilized allogeneic bone sheets in inducing vertebral plate regeneration after laminectomy in sheep.</p><p><b>METHODS</b>Twelve adult male sheep (aged 1.5 years and weighing 27 kg on average) provided by China Institute for Radiation Protection underwent L3-4 and L4-5 laminectomy. Then they were randomly divided into two groups: Group A (n=6) and Group B (n=6). The operated sites of L4-5 in Group A and L3-4 in Group B were covered by "H-shaped" freeze-drying and radiation-sterilized allogeneic bone sheets (the experimental segments), while the operated sites of L3-4 in Group A and L4-5 in Group B were uncovered as the self controls (the control segments). The regeneration process of the vertebral plate and the adhesion degree of the dura were observed at 4, 8, 12, 16, 20 and 24 weeks after operation. X-ray and CT scan were performed in both segments of L3-4 and L4-5 at 4 and 24 weeks after operation.</p><p><b>RESULTS</b>In the experimental segments, the bone sheets were located in the anatomical site of vertebral plate, and no lumbar spinal stenosis or compression of the dura was observed. The bone sheets were absorbed gradually and fused well with the regenerated vertebral plate. While in the control segments, the regeneration of vertebral plate was not completed yet, the scar was inserted into the spinal canal, compressing the dura and the spinal cord, and the epidural area almost disappeared. Compared with the control segments, the dura adhesion degree in the experimental regenerated segments was much milder (P less than 0.01), the internal volume of the vertebral canal had no obvious change and the shape of the dura sack remained well without obvious compression.</p><p><b>CONCLUSIONS</b>Freeze-drying and radiation-sterilized allogeneic bone sheets are ideal materials for extradural laminoplasty due to their good biocompatibility, biomechanical characteristics and osteogenic ability. They can effectively reduce formation of post-laminectomy scars, prevent recurrence of post-laminectomy spinal stenosis, and induce regeneration of vertebral plates.</p>

Preparation of porous polylactic-acid/ bone matrix gelatin composite as scaffold materials for bone-tissue engineering / 南方医科大学学报

<p><b>OBJECTIVE</b>To develop a novel porous poly lactic-acid(PLA)/bone matrix gelatin (BMG) bioactive composite biomaterial with supercritical carbon dioxide (SC-CO2) extraction and determine the optimal proportion of the ingredients by evaluating the physical and chemical characteristics and cellular compatibility of the composites.</p><p><b>METHODS</b>The PLA/BMG composite biomaterials with various PLA/BMG proportions were prepared with SC-CO2 technique and evaluated by macroscopic observation, porosity and mechanical assessment, and scanning electron micrograph (SEM). The optimal proportion of PLA/BMG was determined in conjunction with the results of cellular compatibility evaluation.</p><p><b>RESULTS</b>BMG proportion in BLA/BMG composite biomaterials prepared with SC-CO2 technique was positively associated with the cellular compatibility and porosity, and inversely with the mechanics of the prepared composite. The results showed BMG content of 30% in PLA/BMG composite was optimal.</p><p><b>CONCLUSION</b>The composite with PLA and BMG proportion of 7:3 possesses good physical and chemical characteristics and cellular compatibility, suggesting its potential as the bone implant biomaterial and bone-tissue engineering scaffold.</p>