Objective To find out the recent progress in research of cl inical appl ication of fascia lata allograft. Methods The domestic and international articles were reviewed to summarize the princi pal properties, processing techniques, and various uses of fascia lata allograft. Results Histologically fascia lata is composed of parallel and compact bundles of collagen fibers with few cells and immunologically it is low-antigenic. After varied tissue processing and storage techniques, fascia lata, as the scaffold only with the extracellular matrix, has been used in cl inical practice and achieved good results, such as ophthalmology, urology, and orthopaedics. Conclusion Because of these unique properites in repairing defects and reconstructing functions, fascia lata allograft, as a natural biomaterial, is promising to be used in more aspects withthe development of the biomedical techniques.
Objective To develop a deantigenated porcine bone graft through enzyme treatment and to study the biomechanical properties and osteoinductivity of the xenogeneic bone graft. Methods Deantigenated xenogeneic bone was prepared from porcine bone by a series treatment including α-galactosidase (α-Gal) treatment, freezedrying and irradiation at a does of 25 kGy. Samples were divided into 4 groups according to the treatment methods: fresh bone (group A); deantigenated bone (group B); deantigenated and freezedried bone (group C); deantigenated-freezedried-irradiated bone(group D). SEM observation to group B samples was performed and the diameters of the caves of the porcine cancellous bone were measured. The α-Gal contents of samples of groups A, B, D were measured by ELISA. The effects of different treatments on porcine bone mechanic properties were evaluated through compressive test of 4 groups. The prepared porcine cortical bone were demineral ized and ectopically implanted into muscle groups of hind l imbs of Wistar rats as experimental group, and the demineral ized cortical bone which were inacitviated by high temperature and pressure were implanted as control group. Histological observation was performed and ALP activity was tested at different time postoperatively to investigate the osteoinductivity of the xenogeneic bone implants. Results The porous structure of prepared porcine cancellous bone was similar to that of human cancellous bone. The diameters of the caves were between 150-600 μm. The A value of the groups A, B, D was 0.358 ± 0.027, 0.191 ± 0.011, 0.191 ± 0.009, respectively, with statistically differences between groups (P lt; 0.05). While the biomechanical properties among 4 groups had no statistically difference (P gt; 0.05). Histological observation showed mesenchymal cells immigrated into cartilage and converted into chondrocytes at 3 weeks postoperatively. Cartil iage was formed at 4 weeks and osteoid and more adult cartilage was formed at 6 weeks within the implants of experimental group, while there was no bone formation in control group. ALP activity of experimental group at different times were obviously higher than that of the control group (P lt; 0.05). Conclusion The main xenogeneic antigen of the porcine bone was removed while the mechanic properties and osteoinductivity remained, thus it may be a suitable bone substitute for cl inical use.
【Abstract】 Objective To explore the interventional effect of platelet lysate (PL) on osteogenic differentiation ofBMSCs by induction in rats in vitro. Methods Twenty-four clean-grade adult Wistar rats, weighing from 250 g to 300 g, maleor female, were included in this study. PL was obtained through three times of centrifugation and repeated freeze-thaw for the blood aspirated from cardiac cavities in 16 Wistar rats. ELISA assay was conducted to detect the concentration of growth factors PDGF, TGF-β1, IGF-1 and VEGF in PL. The BMSCs harvested by flushing femurs of 8 adult Wistar rats were isolated, cultivated and expanded in vitro. The cells at the 4 passage were performed for osteogenic differentiation by induction in three groups of A (5% PL of final concentration in basic induction medium), B (1% PL of final concentration in basic induction medium), and C (no presence of PL in basic induction medium as a control). The morphological changes of the cells were dynamically observed with inverted phase contrast microscope during the whole period. At different time-points, ALP staining (7 days) and ALP/TP (2, 8, 12 days) of the cells were detected to evaluate ALP activity, and the mineral formation in extracellular martrix was examined with Al izarin red staining which provided quantitative analysis of mineral deposits. Results ELISA assay showed that the content of PDGF, TGF-β1, IGF-1 and VEGF in PL reached (300 ± 30), (140 ± 25), (80 ± 35), (70 ± 20) pg/mL, respectively. Morphological observation displayed BMSCs in group A or B gradually turned from spindle-shape to square- or polygon-shape as the morphorlogical type of osteoblast-l ike cells at 7 days. The cells in group A showed slower shape changesbut higher prol iferation than that in group B or C. Moreover, at the 20 days, the cells in group A still displayed dense gro wth and produced obviously decreased amount of mineral deposits in ECM when compared with group B or C. At the 7 days, the cells ofgroup A showed smaller amount of granules positive for ALP staining in cytoplasm when compared with groups B and C, and displayed marked reduction in ALP activity assay at the 2, 8, and 10 days compared with that of groups B and C (P lt; 0.05). At the 20 days, Al izarin red staining showed the number of mineral deposits in groups A, B and C were 7.67 ± 1.10, 12.87 ± 0.81 and 15.59 ± 0.25, respectively, while the area of mineral deposits were (161 778.70 ± 44 550.80), (337 349.70 ± 56 083.24), and (415 921.70 ± 71 725.39) pixels, respectively. The number of mineral deposits and the area of mineral deposits in group A were smaller than those in groups B and C (P lt;0.05). But there was no statistically significant difference between groups B and C (P gt; 0.05). Conclusion PL is a kind of system carrying various growth factors. Exposure of PL inhibits both ALP activity and mineral formation of BMCs in a dose-dependent way under the osteogenic induction environment.
Objective To compare the effect of the composite skin graft consisting of spl it-thickness skin grafts (STSGs) and porcine acellular dermal matrix (PADM) with STSGs only, and to histologically observe the turnover of the PADM in rats. Methods Twenty female Sprague-Dawley rats, weighing 200-225 g, were included. The size of 4.0 cm × 2.5 cm PADM was implanted into hypoderm of the left side of Sprague-Dawley rats’ back. After 10-14 days, the size of 4.0 cm × 2.5 cm full-thickness skin defects were made on the left to expose the PADM under the skin and the same size of full-thickness skin defects were made on the right of the rats’ back. The excised full-thickness skin was made to STSGs about 0.2 mm by drum dermatome. The defects were grafted with composite skin (STSGs on the PADM, experimental group) and STSGs only (control group). The survival rate, the constraction degree of grafts, and the histological change in grafts area were observed at 2, 4, 8, and 20 weeks after operation. Results At 2 weeks after STSGs (0.2 mm) placed on vascularized PADM, STSGs and PADM adhered together and the composite skin had a good survival. The control group also had a good survival. Histological observations showed that STSGs and PADM grew together, neutrophil ic granulocytes and lymphocytes infiltrated in the PADM and some macrophages around the PADM. Fibrous connective tissues were filled under the STSGs in control group. At 4-8 weeks after transplantation, the composite skin had a good survival and the composite skin was thick, soft, and elastic. STSGs survived almost totally in control group, but the grafts were thin. Histological observations showed that inflammatory reactions of PADM faded gradually in experimental group; scar tissues formed under the STSGs in control group. At 20 weeks after transplantation, composite skin was flat, thick, and elastic in experimental group, but the STSGs were thinner and less elastic in control group. Histological observations showed that histological structures of the PADM were similar to the dermal matrix of rats, and the results showed that the collagen matrix of PADM was gradually replaced by the rats’ collagen matrix. Scar tissues were filled under the STSGs in control group. Wound heal ing rates of experimental group were lower than those of control group at 4 and 8 weeks (P﹤0.05); wound contraction rates of experimental group had lower tendency than those of control group, but showing no significant differences (P gt; 0.05). Conclusion Coverage wound with composite skin which composed of STSGs and PADM could improve wound heal ing qual ity; the composite skin is thicker and better elastic than STSGs only. The collagen matrix of PADM is gradually replaced by rats’ collagen matrix.