ObjectiveTo investigate the feasibil ity and effectiveness of using scar spl it thickness skin grafts combined with acellular allogeneic dermis in the treatment of large deep Ⅱ degree burn scar. MethodsBetween January 2013 and December 2013, 20 cases of large deep Ⅱ degree burn scar undergoing plastic operation were enrolled. There were 14 males and 6 females, aged 4 to 60 years (mean, 40 years). Burn reasons included hydrothermal burns in 10 cases, flame burns in 9 cases, and lime burns in 1 case. The burn area accounted for 70% to 96% total body surface area (TBSA) with an average of 79% TBSA. The time from wound healing to scar repair was 3 months to 2 years (mean, 7 months). Based on self-control, 0.7 mm scar spl it thickness skin graft was used to repair the wound at the right side of joints after scar resection (control group, n=35), 0.5 mm scar spl it thickness skin graft combined with acellular allogeneic dermis at the left side of joints (trial group, n=30). Difference was not statistically significant in the scar sites between 2 groups (Z=-1.152, P=0.249). After grafting, negative pressure drainage was given for 10 days; plaster was used for immobilization till wound heal ing; and all patients underwent regular rehabil itation exercises. ResultsNo significant difference was found in wound heal ing, infection, and healing time between 2 groups (P>0.05). All patients were followed up for 6 months. According to the Vancouver Scar Scale (VSS), the score was 5.23±1.41 in trial group and was 10.17±2.26 in control group, showing significant difference (t=8.925, P=0.000). Referring to Activities of Daily Living (ADL) grading standards to assess joint function, the results were excellent in 8 cases, good in 20 cases, fair in 1 case, and poor in 1 case in trial group; the results were excellent in 3 cases, good in 5 cases, fair in 22 cases, and poor in 5 cases in control group; and difference was statistically significant (Z=-4.894, P=0.000). ConclusionA combination of scar spl it thickness skin graft and acellular allogeneic dermis in the treatment of large deep Ⅱ degree burn scar is feasible and can become one of solution to the problem of skin source tension.
Objective To compare the difference of preparing the acellular larynx scaffold between perfusion method and immersion method, and find better way to make acellular larynx scaffold for tissue engineering. Methods Twenty 6-month-old male New Zealand rabbits, weighing 2.0-2.5 kg, were divided into perfusion group (n=10) and immersion group (n=10) at random. All the larynxes were excised in a sterile fashion. The acellular larynx scaffold was obtained by perfusionmethod and immersion method respectively, and then comparative examinations were performed by the macroscopicview, histological view, scanning electron microscope (SEM), cartilage vital ity assay and toluidine blue staining. ResultsMacroscopic view showed that the larynxes perfused by sodium dodecyl sulphate (SDS) became transparent after 2 hoursof perfusion, but the larynxes immersed by SDS over 16 hours still appeared pink-white. Histology and SEM indicated thatcompared with immersion group, perfusion group showed better acellular effect, more ventages and collagen fibers wereretained, no intact cell or nuclei remained in acellular matrix and chondrocytes were still survival. The porosity was 85.39% ± 3.16% in perfusion group and 34.72% ± 4.51% in immersion group, showing significant difference (P lt; 0.01). The chondrocyte vital ity rate of perfusion group (86.93% ± 1.52%) was higher than that of immersion group (77.73% ± 1.66%), showing significant difference (P lt; 0.01). Toluidine blue staining showed that the chondrocyte heterochromaty was ber in perfusion group than that in immersion group. Conclusion Compared with immersion method, perfusion method is a better way to construct acellular larynx scaffold because it can achieve better acellular effect and retain chondrocyte vital ity at the greatest extent in the acellular larynx scaffold.
Objective To investigate the possible mechanism of the fibroblasts inducing the vascularization of dermal substitute. Methods Fibroblasts were seeded on the surface of acellular dermal matrix and cultivated in vitro to construct the living dermal substitute. The release of interleukin 8 (IL 8) and transfonming growth factor β 1(TGF β 1) in culture supernatants were assayed by enzyme linked immunosorbent assay, the mRNA expression of acid fibroblast growth factor (aFGF) and basic fibroblast growth factor (bFGF) were detected by RT-PCR. Then, the living substtute was sutured to fullth ickness excised wound on BALBouml;C m ice, and the fate of fibroblast w as observed by using in situ hybridizat ion. Results Fibroblasts cultured on acellular dermalmat rix p ro liferated and reached a single2layer confluence. Fibroblasts could secret IL 28 (192. 3±15. 9) pgouml;m l and TGF-B1 (1. 105±0. 051) pgouml;m l. There w as the mRNA exparession of aFGF and bFGF. Fibroblasts still survived and proliferated 3 weeks after graft ing. Conclusion Pept ides secreted by fibroblasts and its survival after graft ing may be relat ive to the vascularizat ion of the dermal subst itute.
Objective To study the migration of Schwann cells from the nerve autograft in the acellular nerve allograft of the rats in vivo. Mehtods The sciatic nerves (20 mm long) of the SD rats were harvested and prepared for the acellular nerve grafts by the chemical extraction. Then, they were observed by the gross view, HE staining, and Antilamininstaining, respectively. Another 32 female SD rats weighing 250-300 g were obtained for the study. A 2-mm-long nerve autograft was interposed between the two 10-mm-long nerve allografts to form a 22-mm-long composite. Then, the composite was placed in the muscle space, together with a sole 22-mm-long nerve allograftas a control. They were harvested at 5，10，15 and 20 days, respectively, and were then given the HE staining and the S-100 staining. Results The acellular nerve graft was semitransparent under the gross view. HE staining showed that no cell was observed within the nerve graft. Anti-laminin staining showed that the basal membrane was partially interrupted, with a positive result (dark brown). All the nerve grafts in both the groups exhibited the existenceof the cells. The S-100 positive cells were observed from the 15th day at the far ends of the two allografts of the composite; however, there were no suchcells observed within the sole nerve allograft. Conclusion Schwann cells from the sciatic nerves (2 mm- long) of the rats can migrate in the acellular nerve allograft to the far ends of the neighboring 10-mm-long nerve allografts at 15 days after operation, which offers the theoretical basis forthe repair of the longrange nerve defect by the composite of the acellular nerve allografts with the interposed nerve autograft.
In the past fifty more years, many research results have been achieved in the field of artificial esophagus which has been a major subject of surgical study on esophagus. Unfortunately,a very satisfactory artificial esophagus has not been found due to lack of proper artificial materials and problems of postoperative complications which results in great hindrance to applying them to clinical purpose. The current research focuses on artificial esophaguses constructed with acellular matrix as well as constructed through tissue engineering,furthermore,how to prevent and cure postoperative complications is still the main difficulty. This paper gives an overview of the recent study results,points in dispute, present status of research and the recent advances, and an overview to the future of artificial esophagus.
ObjectiveTo compare the half-year clinical efficacy of three different surgical root coverage methods including lateral sliding flap (LSF), subepithelial connective tissue graft (CTG) and acellular dermal matrix allograft (ADM). MethodsEighteen patients (24 teeth) with gingival recession treated in our hospital between December 2012 and July 2015 were selected and divided into three groups according to a certain sequence with 8 teeth in each group. The three groups of teeth were treated with LSF, CTG and ADM respectively. Gingival recession, probing depth and keratinized gingival width at both baseline and 6 months after surgery of all patients were recorded for inner- and inter-group comparison. ResultsAll three methods proved to be effective within 6 months with an awerage of 2.8-4.0 mm in decrease extent of gingival recession (P<0.01). LSF did not significantly change the probing depth (P>0.05) as the other two did (P<0.01). The differences among three surgical methods compared before and after surgery were all significant (P<0.05). ConclusionLSF, CTG and ADM are all effective surgical means for root coverage. Within 6 months, CTG presents better effects than ADM, and ADM better than LSF.
OBJECTIVE: To explore the possibility of detergent acellularized porcine heart valve serving as a scaffold for tissue engineering valve. METHODS: The porcine aortic valves were acellularized by use of trypsin-EDTA. Triton X-100, RNase and DNase treatment. Biomechanical characteristics of fresh valves and acellularized valve were tested; also fresh valves, acellularized valve and valves treated with method of bioprothetic treatment were implanted subcutaneously in rats; frequently seeded with bovine aortic endothelial cells(BAECs), and then cultured for 7 days. RESULTS: The acellularization procedure resulted in complete removal of the cellular components while the construction of matrix was maintained. The matrix could be successfully seeded with in vitro expanded BAECs, which formed a continuous monolayer on the surface. There is no significant difference of PGI2 secretion of BAECs between cells seeded onto the acellular leaflets and that onto the wells of 24-wells plate (P gt; 0.05). CONCLUSION: Acellularied porcine aortic valve can be applied as a scaffold to develop tissue engineering heart valve.
OBJECTIVE: To explore the possibility to bridge peripheral nerve defects by xenogeneic acellular nerve basal lamina scaffolds. METHODS: Thirty SD rats were randomly divided into 5 groups; in each group, the left sciatic nerves were bridged respectively by predegenerated or fresh xenogeneic acellular nerve basal lamina scaffolds, autogenous nerve grafting, fresh xenogeneic nerve grafting or without bridging. Two kinds of acellular nerve basal lamina scaffolds, extracted by 3% Triton X-100 and 4% deoxycholate sodium from either fresh rabbit tibial nerves or predegenerated ones for 2 weeks, were transplanted to bridge 15 mm rat sciatic nerve gaps. Six months after the grafting, the recovery of function was evaluated by gait analysis, pinch test, morphological and morphometric analysis. RESULTS: The sciatic nerve function indexes (SFI) were -30.7% +/- 6.8% in rats treated with xenogeneic acellular nerve, -36.2% +/- 9.7% with xenogeneic predegenerated acellular nerve, and -33.9% +/- 11.3% with autograft respectively (P gt; 0.05). The number of regenerative myelinated axons, diameter of myelinated fibers and thickness of myelin sheath in acellular xenograft were satisfactory when compared with that in autograft. Regenerated microfascicles distributed in the center of degenerated and acellular nerve group. The regenerated nerve fibers had normal morphological and structural characters under transmission electron microscope. The number and diameter of myelinated fibers in degenerated accellular nerve group was similar to that of autograft group (P gt; 0.05). Whereas the thickness of myelin sheath in degenerated accellular nerve group was significantly less than that of autograft group (P lt; 0.05). CONCLUSION: The above results indicate that xenogeneic acellular nerve basal lamina scaffolds extracted by chemical procedure can be successfully used to repair nerve defects without any immunosuppressants.
ObjectiveTo investigate the effects of modification of acellular bovine pericardium with 1-ethyl-3-(3-dinethylami-nopropyl) carbodimide (EDC)/N-hydroxysuccininide (NHS) or genipin and find out the best crosslinking reagent. MethodsThe cellular components of the bovine pericardiums were removed. The effects of decellularization were tested by HE staining. The acellular bovine pericardiums were crosslinked with EDC/NHS (EDC/NHS group) or genipin (genipin group). The properties of the crosslinked acellular matrix were evaluated by scanning electron microscope (SEM), matrix thickness, crosslinking index, mechanical property, denaturation temperature, enzymatic degradation, and cytotoxicity test before and after the crosslinking. Acellular bovine pericardium (ABP group) or normal bovine pericardium (control group) were harvested as controls. ResultsSEM showed that collagen fibers were reticulated in bovine pericardial tissues after crosslinked by EDC/NHS or genipin, and relative aperture of the collagen fiber was from 10 to 20 μm. The thickness and denaturation temperature of the scaffolds were increased significantly after crosslinking with EDC/NHS or genipin (P<0.05), while there was no significant difference between EDC/NHS group and genipin group (P>0.05). The difference had no statistical significance in crosslinking index between EDC/NHS group and genipin group (t=0.205, P=0.218). The degradation rate in EDC/NHS group and genipin group was significantly lower than that in ABP group and control group (P<0.05). Elastic modulus and fracture stress in EDC/NHS group and genipin group were significantly lower than those in ABP group (P<0.05), but there was no significant difference among EDC/NHS group, genipin group, and control group (P>0.05). The break elongation in EDC/NHS group and genipin group were significantly increased than those in ABP group and control group (P<0.05). The difference had no statistical significance in stability and mechanical properties between EDC/NHS group and genipin group (P>0.05). Cytotoxicity of genipin crosslinked tissue (grade 1) were much lower than that of EDC/NHS (grade 2) at 5 days. ConclusionAcellular bovine pericardium crosslinked with genipin has better biocompatibility than EDC/NHS.
Objective To choose the best procedure on preparation of acellularbovine pericardium (ABP) guided bone regeneration (GBR) material. Methods The BP was decellularized with 0.25% Trypsin+0.5% Triton X-100. The acellular bovine pericardiums (ABPs) were treated with phosphatebuffered saline(PBS) (group A), 95% glycerol (group B), EDAC (group C), and EDAC and 95% glycerol (group D) respectively. The treated ABPs were implanted subcutaneously in the back of SD rats respectively at random and no material was implanted as control. Seven rats were sacrificed at 2 weeks, twelve at 4 weeks, twelve at 8 weeks, seven at 16 weeks. Local reaction was studied grossly. The amount of antigen presenting cell (APC) and the percentage of ABP degeneration were reckoned by images analysis system. Results The ABPs were replaced by fibroblasts completely in group A at 8 weeks， in group C at 16 weeks, but only less than 50% till 16 weeks in groups B and D. In all groups, the depth of surrounding fibres attenuated timedependingly. The APC amount of the groups B and D was higher than that of the control group, and the ABP of the groups B and D degraded partly at 16 weeks. Conclusion The ABP treated with EDAC can be replaced by the surrounding tissues and has good biocompatibility.