OBJECTIVE To investigate the methods to fabricate repair materials of tissue engineered peripheral nerve with bioactivity of Schwann cells (SC). METHODS 1. The materials were made by dry-wet spinning process to fabricate PLA hollow fiber canal with external diameter of 2.3 mm, internal diameter of 1.9 mm, thickness of 0.4 mm, pore size of 20 to 40 microns, pore ratio of 70% and non-spinning fiber net with pore size of 100 to 200 microns, pore ratio of 85%. 2. SC were implanted into excellular matrix (ECM) gel to observe the growth of SC. 3. SC/ECM complex were implanted into non-spinning PLA fiber net to observe the growth of SC. 4. SC, SC/ECM and SC/ECM/PLA were implanted into PLA hollow fiber canal to bridge 10 mm defect of rat sciatic nerve. RESULTS 1. SC were recovered bipolar shape at 1 day after implantation, and could be survived 14 days in ECM gel. 2. After SC/ECM complex was implanted into PLA net, most of SC were retained in the pore of PLA net with the formation of ECM gel. SC could be adhered and grown on PLA fiber. 3. Most of SC in ECM gel could be survived to 21 days after transplantation. Survival cell numbers of SC/ECM and SC/ECM/PLA groups were obviously higher than SC suspension group. CONCLUSION Non-spinning PLA porous biodegradable materials with ECM is benefit for SC to be adhered and grown.
Objective To evaluate an effect of the vascularendothelial growth factor (VEGF) geneactivated matrix (GAM) on repair of the sciatic nerve defect in rats. Methods The peripheral nerve extracellular matrix（ECM） was harvested by the chemical extraction from 30 SD rats. The VEGF-GAM comprised of ECM and the plasmids encoding VEGF. Thirty adult Wistar rats were made as a model of the asciatic nerve defect and were randomly divided into the following 3 groups(n=10): Group A (VEGF-GAM conduits), Group B (ECM conduits),and Group C (autografts). At 12 weeks, the rats from each groupwere subjected to an inspection for the walking tract analysis and electrophysiological and histomorphological studies.Results The VEGF DNA could be retained in GAM, promoting the transgene expressing in the sciatic nerve, and more importantly, in the axotomized neurons in the spinal cord for 12 weeks. The motor neuron recovery rate in Group A (79.13％±2.53％) was similar to that in Group C (75.26％±4.48％, Pgt;0.05), but significantly better than that in Group B (56.09％±1.89％, Plt;0.01). The number of the regenerationaxons in the distal sciatic nerve in Group A (13 463±794/mm2) was significantly lower than that in Group C (16 809±680/mm2, Plt; 0.01), but significantly higher than that in Group B (10 260±1 117/mm2,Plt;0.01). The motor nerve conduction velocity in Group A (16.44±1.65 m/s) was significantly lowerthan that in Group C (23.79±2.75 m/s, Plt;0.01), but significantly higherthan that in Group B (12.8 ±1.42 m/s, Plt;0.01). The recovery rate of thegastrocnemius muscle wet weight in Group A (71.40％±3.05%) was significantlylower than that in Group C (87.00％±1.87％,Plt;0.01), but significantly higher than that in Group B (50.00％±4.90％, Plt;0.01). The sciatic nerve function index in Group A （39.37%±4.81%） was significantly lower 〖KG6〗than that in Group C (26.27%±2.71%, Plt;0.01), but significantly higher than that in Group B (4693％±296％, Plt;0.01). Conclusion The results indicate that VEGF-GAM as a bridge can promote the functional recovery of the defected sciatic nerve in rats, but the effect is not so good as that by autografts.
This paper reviewed the main achievements in the research on tissue engineering tendon, focusing on major problems concerning the substitute for extracellular matrix (ECM) of tendon, biological characteristics of tendon cells, and tendon cells compounding with ECM substitute. It was concluded the important problems in the study of the tissue engineering having specific reparative functions could be: to prepare the ECM materials suitable for the tendon cells to attach, grow, and function; to establish the tendon cell line whose growth, proliferation, and immunological antigenicity could be modulated and controlled, and simulating the mechanical environment of tendon in vivo, to adopt three-dimensional tendon cell culture method.
Objective To review the decellularized methods for obtaining extracellular matrix (ECM) and the applications of decellularized ECM scaffold in tissue engineering. Methods Recent and related literature was extensively and comprehensively reviewed. The decellularized methods were summarized and classified. The effects of different sterilization methods on decellularized scaffolds were analyzed; the evaluation criterion of extent of decellularization was put forward; and the application of decellularized ECM scaffold in different tissues and organs engineering field was summarized. Results The decellularized methods mainly include physical methods, chemical methods, and biological methods, and different decellularization methods have different effects on the extent of cell removal and ECM composition and structure. Therefore, the best decellularization method will be chosen according to the characteristics of the tissues and decellularization methods to achieve the ideal result. Conclusion It is very important to choose the appropriate decellularized method for preparing the biological materials desired by tissue engineering. The biological scaffolds prepared by decellularized methods will play an important role in tissue engineering and regenerative medicine.
OBJECTIVE: To review the role of matrix metalloproteinase-1 (MMP-1) in the course of healing in wounded skin. METHODS: The recent literatures on MMP-1 in skin wound repair were reviewed, which gave the insight into the local effect of MMP-1 during re-epithelialization. RESULTS: Following injury, basal keratinocytes, moving from the wound edge and interact with dermal matrix proteins in the wound bed, were induced to express MMP-1 in a specific space-time pattern. MMP-1 cleaved the collagen, thereby altering its structure and affinity by which the keratinocytes binded it. MMP-1 served a beneficial role in wound healing by facilitating the proliferation and movement of keratinocytes over the collagen-rich wound bed during re-epithelialization. CONCLUSION: MMP-1 expression of migrating keratinocytes directly influences the re-epithelialization during the course of healing of the wounded skin.
ObjectiveTo review the advances in utilizing paracrine effect of stem cells in knee osteoarthritis (OA) treatment.MethodsThe researches in applying stem cells derived conditioned medium, extracellular matrix, exosomes, and microvesicles in knee OA treatment and cartilage repair were reviewed and analyzed.ResultsThe satisfying outcomes of using different products of stem cells paracrine effect in knee OA condition as well as cartilage defect is revealed in studies in vitro and in vivo. The mechanism including suppressing the intraarticular inflammation, the apoptosis of chondrocytes, and the degradation of cartilage matrix, while enhancing the synthesis of cartilage matrix, the differentiation of in-situ stem cells into chondrocytes and the migration to the affected area. The effectiveness can be further improved supplemented with the tissue engineering methods or gene modification.ConclusionCompared with the traditional stem cell therapy, applying the products from paracrine effect of stem cells in knee OA treatment is more economical and safer, presenting great potential in clinical practice.
OBJECTIVE: To investigate the preparation of bone acellular extra-cell matrix(AECM) and to analyze its component. METHODS: With low-osmosis theory and method of cell extraction by detergent, bone acellular extra-cell matrix was prepared. We observed morphologic changes with HE, Mallory-Heidenhain rapid one-step dyeing and Alcian blue dyeing and examined fibronectin(FN) and laminin(LN) with immunohistochemistry. RESULTS: Light microscope showed that the collagen fibers arranged regularly in AECM with blankness of bone lacunas by HE, Mallory-Heidenhain rapid one-step dyeing and that the region around bone lacunas was stained different degrees of blue-green by Alcian blue dyeing. The result of immunohistochemistry showed there are positive markers of FN and LN in ECM. CONCLUSION: This method for preparation of bone acellular extra-cell matrix is effective, and it can keep natural structure of collagen fibers and maintain components of ECM, such as proteoglycan, FN and LN.
The chemical extraction method was used to prepare the rat uterine decellularized scaffolds, and to investigate the feasibility of preparing the extracellular matrix (ECM) hydrogel. The rat uterus were collected and extracted by 1%sodium dodecyl sulfate (SDS), 3% TritonX-100 and 4% sodium deoxycholate (SDC) in sequence. Scanning electron microscopy, histochemical staining and immunohistochemistry was used to assess the degree of decellularization of rat uterine scaffold. The prepared decellularized scaffold was digested with pepsin to obtain a uterine ECM hydrogel, and the protein content of ECM was determined by specific ELISA kit. Meanwhile, the mechanical characteristic of ECM hydrogel was measured. The results showed that the chemical extraction method can effectively remove the cells effectively in the rat uterine decellularized scaffold, with the ECM composition preserved completely. ECM hydrogel contains a large amount of ECM protein and shows a good stability, which provides a suitable supporting material for the reconstruction of endometrium in vitro.
Objective To investigate the effect of porcine small intestinal submucosa extracellular matrix (PSISM) on the vitality and gene regulation of hepatocyte so as to lay the experimental foundation for the application of PSISM in liver tissue engineering. Methods The experiment was divided into two parts: ① BRL cells were cultured with 50, 100, and 200 μg/mL PSISM-medium which were prepared by adding PSISM into the H-DMEM-medium containing 10%FBS in groups A1, B1, and C1, and simple H-DMEM-medium served as a control (group D1); ② BRL cells were seeded on 1%, 2%, and 3% PSISM hydrogel which were prepared by dissolving PSISM in sterile PBS solution containing 0.1 mol/L NaOH in groups A2, B2, and C2, and collagen type I gel served as a control (group D2). At 1, 3, and 5 days after culture, the morphology and survival of liver cells were detected by the Live/Dead fluorescent staining. The cell vitality was tested by cell counting kit-8 (CCK-8) assay. And the relative expressions of albumin (ALB), cytokeratin 18 (CK18), and alpha-fetoprotein (AFP) in hepatocytes were determined by real-time fluorescent quantitative PCR (RT-qPCR). Results The Live/Dead fluorescent staining showed the cells survived well in all groups. CCK-8 results displayed that the absorbance (A) value of group C1 was significantly higher than that of group D1 at 5 days after culture with PSISM-medium, and there was no significant difference between groups at other time points (P>0.05). After cultured with PSISM hydrogels, theA values of groups A2, B2, and C2 were significantly higher than those of group D2 at 3 and 5 days (P<0.05), theA value of group A2 was significantly higher than that of groups B2 and C2 at 5 days (P<0.05), but there was no significant difference between groups at other time points (P>0.05). RT-qPCR showed that the relative expressions of ALB and CK18 mRNA significantly increased and the relative expression of AFP mRNA significantly decreased in groups A1, B1, and C1 when compared with group D1 (P<0.05). The relative expression of CK18 mRNA in group C1 was significantly lower than that in groups A1 and B1 (P<0.05). The relative expressions of ALB and CK18 mRNA were significantly higher and the relative expression of AFP mRNA was significantly lower in groups A2, B2, and C2 than group D2 (P<0.05); the relative expression of CK18 mRNA in group A2 was significantly higher than that in group B2 (P<0.05), and the relative expression of AFP mRNA in group A2 was significantly lower than that in group C2 (P<0.05), but no significant difference was found between other groups (P>0.05). Conclusion PSISM has good compatibility with hepatocyte and can promote the vitality and functional gene expression of hepatocyte. PSISM is expected to be used as culture medium supplement or cell carrier for liver tissue engineering.
Aortic aneurysm and dissection are critical cardiovascular diseases that threaten human life and health seriously. No pharmacological treatment can effectively prevent disease progression. The imbalance of aortic wall cells and non-cellular components leads to structural or functional degeneration of the aorta, which is a prerequisite for disease occurrence. As the important non-cellular component, extracellular matrix (ECM) is crucial to maintain the aortic structure, function, and homeostasis. Abnormal production of elastin and collagen, destruction of cross-linking between elastic fibers and collagen fibers, and the imbalance of metalloproteinase and inhibitors leads to excessive degradation of ECM proteins, all of which have destroyed the structure and function of aorta. It will provide more ideas for disease prevention and treatment by learning ECM proteins and their metabolic mechanism. Here, we focus on the ECM proteins that have been reported to be involved in aortic aneurysm and dissection, and discuss the regulatory mechanism of metalloproteinase and inhibitors.