Objective To study the outcomes of nerve defect repair with the tissue engineered nerve, which is composed of the complex of SCs, 30% ECM gel, bFGF-PLGA sustained release microspheres, PLGA microfilaments and permeable poly (D, L-lacitic acid) (PDLLA) catheters. Methods SCs were cultured and purified from the sciatic nerves of 1-day-old neonatal SD rats. The 1st passage cells were compounded with bFGF-PLGA sustained release microspheres andECM gel, and then were injected into permeable PDLLA catheters with PLGA microfilaments inside. In this way, the tissueengineered nerve was constructed. Sixty SD rats were included. The model of 15-mm sciatic nerve defects was made, and then the rats were randomly divided into 5 groups, with 12 rats in each. In group A, autograft was adopted. In group B, the blank PDLLA catheters with PBS inside were used. In group C, PDLLA catheters, with PLGA microfilaments and 30% ECM gel inside, were used. In group D, PDLLA catheters, with PLGA microfilaments, SCs and 30% ECM gel inside, were used. In group E, the tissue engineered nerve was appl ied. After the operation, observation was made for general conditions of the rats. The sciatic function index (SFI) analysis was performed at 12, 16, 20 and 24 weeks after the operation, respectively. Eelectrophysiological detection and histological observation were performed at 12 and 24 weeks after the operation, respectively. Results All rats survived to the end of the experiment. At 12 and 16 weeks after the operation, group E was significantly different from group B in SFI (P lt; 0.05). At 20 and 24 weeks after the operation, group E was significantly different from groups B and C in SFI (P lt; 0.05). At 12 weeks after the operation, electrophysiological detection showed nerve conduct velocity (NCV) of group E was bigger than that of groups B and C (P lt; 0.05), and compound ampl itude (AMP) as well as action potential area (AREA） of group E were bigger than those of groups B, C and D (P lt; 0.05). At 24 weeks after the operation, NCV, AMP and AREA of group E were bigger than those of groups B and C (Plt; 0.05). At 12 weeks after the operation, histological observation showed the area of regenerated nerves and the number of myel inated fibers in group E were significantly differents from those in groups A, B and C (Plt; 0.05). The density and diameter of myel inated fibers in group E were smaller than those in group A (Plt; 0.05), but bigger than those in groups B, C and D (P lt; 0.05). At 24 weeks after the operation, the area of regenerative nerves in group E is bigger than those in group B (P lt; 0.05); the number of myel inated fibers in group E was significantly different from those in groups A, B, C (P lt; 0.05); and the density and diameter of myel inated fibers in group E were bigger than those in groups B and C (Plt; 0.05). Conclusion The tissue engineered nerve with the complex of SCs, ECM gel, bFGF-PLGA sustained release microspheres, PLGA microfilaments and permeables PDLLA catheters promote nerve regeneration and has similar effect to autograft in repair of nerve defects.
Objective To develop three-dimensional (3D) porous nanofiber scaffold of PLGA-silk fibroincollagen and to investigate its cytocompatibil ity in vitro. Methods Method of electrostatic spinning was used to prepare 3D porous nanofiber scaffold of PLGA-silk fibroin-collagen (the experimental group) and 3D porous nanofiber scaffold of PLGA (the control group). The scaffold in each group was observed by scanning electron microscope (SEM). The parameters of scaffold fiber diameter, porosity, water absorption rate, and tensile strength were detected. SC harvested from the bilateral brachial plexus and sciatic nerve of 8 SD suckl ing rats of inbred strains were cultured. SC purity was detected by S-100 immunohistochemistry staining. The SCs at passage 4 (5 × 104 cells/mL) were treated with the scaffold extract of each group at a concentration of 25%, 50%, and 100%, respectively; the cells treated with DMEM served as blank control group. MTT method was used to detect absorbance (A) value 1, 3, 5, and 7 days after culture. The SC at passage 4 were seeded on the scaffold of the experimental and the control group, respectively. SEM observation was conducted 2, 4, and 6 days after co-culture, and laser scanning confocal microscope (LSCM) observation was performed 4 days after co-culture for the growth condition of SC on the scaffold. Results SEM observation: the scaffold in two groups had interconnected porous network structure; the fiber diameter in the experimental and the control group was (141 ± 9) nm and (205 ± 11) nm, respectively; the pores in the scaffold were interconnected; the porosity was 87.4% ± 1.1% and 85.3% ± 1.3%, respectively; the water absorption rate was 2 647% ± 172% and 2 593% ± 161%, respectively; the tensile strength was (0.32 ± 0.03) MPa and (0.28 ± 0.04) MPa, respectively. S-100 immunohistochemistry staining showed that the SC purity was 96.5% ± 1.3%. MTT detection: SC grew well in the different concentration groups and the control group, the absorbance (A) value increased over time, significant differences were noted among different time points in the same group (P lt; 0.05), and there was no significant difference between the different concentration groups and the blank control group at different time points (P gt; 0.05). SEM observation: in the experimental group, SC grew well on the scaffold, axon connection occurred 4 days after co-culture, the cells prol iferated massively and secreted matrix 6 days after co-culture, and the growth condition of the cells was better than the control group. The condition observed by LSCM 4 days after co-culture was the same as that of SEM. Conclusion The 3D porous nanofiber scaffoldof PLGA-silk fibroin-collagen prepared by the method of electrostatic spinning is safe, free of toxicity, and suitable for SC growth, and has good cytocompatibil ity and proper aperture and porosity. It is a potential scaffold carrier for tissue engineered nerve.
【Abstract】 Objective To evaluate the effectiveness of percutaneous fixation with il iosacral screw in the management of unstable pelvic fractures. Methods From March 2003 to January 2007, 15 patients with unstable pelvic fractures were treated by percutaneous fixation with il iosacral screws. There were 6 males and 9 females, aged 21-56 years. Fractures were caused by traffic accident in 8 cases, high fall ing in 6 cases and crushing injury in 1 case. The disease course ranged from 4 hours to 3 days. Of 15 patients, 7 had fractures of pubium and sacrum; 2 had fractures of il ium and sacrum; 4 had dislocation of sacroil iac joint with fractures of pubic rami; and 2 had dislocation sacroil iac joint with fracture of sacrum of pubium. Anterior fixation was performed by means of plating in 3 cases, by external fixation in 7 cases, and by both in 5 cases. Results The blood loss was from 1 000 to 1 500 mL in 4 patients with acetabular fracture and about 50 mL in the others. The average operative time was 153.6 minutes (range, 60-305 minutes). Fifteen patients were followed up 6 months to 3 years with an average of 18months. According to Matta criterion for fracture reduction, the results were excellent in 14 cases and good in 1 case. After a follow-up of 28.8 months, fracture union was achieved in all patients. Screw loosening occurred in 1 case, pain of lumbosacral region in 3 cases after tiredness and mild claudication in 2 cases. Nine patients returned to their occupation, three patients changed occupation, and 3 patients could not work at last follow-up. According to Majeed functional scoring, the results were excellent in 11 cases and good in 4 cases. Conclusion Percutaneous il iosacral screw fixation is a useful method in treatment of unstable pelvic fracture.