Objective To observe the efficacy of hydrogel dressings in preventing and treating vein injury of rabbits so as to provide a experimental evidence for cl inical appl ication. Methods Twenty-four healthy large-eared Japanese rabbits (48 ears) were choosen, weighing (2.15 ± 0.15) kg, and divided into 3 groups randomly. The vein injury models were made byintravenously infusing 20% mannite (2.5 mL/kg). The sites of puncture were treated with hydrogel dressings (group A, n=8) and 25%MgSO4 (group B, n=8) 5 minutes after infusion. The sites of puncture were not treated as a blank control (group C, n=8). The tissue specimens were collected from the auricular veins at 24 hours after mannite infusion for histological observation by HE staining. The injury of the vessel wall, hemorrhage around the vessels, infiltration of inflammatory cells, and disturbance of circulation were observed to evaluate the injury degree of vein. Results There existed redness and congestion in the injured veins of each group. HE staining showed that in both groups A and B, the vessel wall was sl ightly injured and hemorrhage around the vessel was mild. There existed infiltration of inflammatory cells in the vessel wall and surrounding tissues. There also existed congestion and thrombus in the vessel lumen in these two groups. While in group C, the injury of vessel wall was severe, and schistic bleeding in the surrounding tissue of the vessel was existed. The severe congestion and thrombus in the vessel lumen was observed. There was no significant difference among three groups in the extent of vein wall injury and hemorrhage around the vessel (P gt; 0.05). The degree of infiltration of inflammatory cells and circulatory disturbance in both groups A and B were significantly less than that of group C (P lt; 0.05); but there was no significant difference between groups A and B (P gt; 0.05). Conclusion Hydrogel dressing is helpful to prevent vein injury of rabbits induced by mannite.
【Abstract】 Objective To increase the viscosity of chitosan/glycerol phosphate（C/GP）and to improve its preparation technique in order to develop the appl ication range of C/GP. Methods Chitosan was treated by high-pressure vapor steril ization in order to prepare high viscous C/GP（HV-C/GP）and prepare C/GP by standard methods. The rheologic changes of HV-C/GP and C/GP were detected dynamically by the Gemini rheometer. The initial solution viscosity, gelation temperature and gelation time were evaluated after the viscosity of the materials were increased. Two gelation materials were placed into continuous flow thermostated cells under the same condition and harvest them at predetermined time intervals, 1st, 2nd, 5th, 10th and 25th days, then they were dried, weighed and the mass loss rate was calculated. Ultrastructure of the freeze-dried samples was visual ized by the scanning electron microscope. Results The initial viscosity of C/GP was 1.81 Pas and that of HV-C/GP was 17.24 Pas. The latter one increased 10 times as well as the former one. The gelation temperature of C/GP was 37°C and that of HV-C/GP was 34°C. There was no remarkable difference in gelation time between them. The mass loss rate of HV-C/GP at first day was 72.5% and at 25th days was 90.8%, while that of C/GP was 55.4% and 78.2%. Porous network structure was observed by the scanning electron microscope in both of them. The pore diameter of C/GP was 50-100 μm and that of HV-C/GP was 30-50 μm, which was obviously smaller than the former. Conclusion The viscosity of HV-C/GP prepared by improved technique obviously increases and the thermosensitivity has no significant changes. The degradation time of HV-C/GP in vitro lengthens. The micrographs show that the HV-C/GP gels are porous and the pore diameter are smaller than C/GP.
Objective To introduce the development of dextran-based hydrogel and its drug delivery system in drug sustained and/or controlled release, and to investigate their application in tissue engineering.Methods Related literature was extensively reviewed and comprehensively analyzed. Results In recent years, great progress was made in the studies of dextran-based hydrogels and study on dextran-based intelligent materials became an investigative hotspot especially in tissue engineering. Conclusion Dextran based hydrogel is considered to be a good potential material in field of drug delivery and tissue engineering. Endowed with new characteristics, a series of intelligent biomaterials can be derived from dextran-based hydrogels, which can be widely used in biomedicine. Further study should be done on the industrialization of its interrelated production.
OBJECTIVE: To investigate the effect of compound pattern of ceramic bovine bone (CBB) and hydrogel(HG) on attachment, proliferation and differentiation of bone marrow stromal cell (MSC), and to find out the best way of constructing tissue engineered bone. METHODS: CBB, HG and MSC was compounded in different patterns and sequences to form CBB/HG/MSC (group A), HG/MSC/CBB (group B), CBB/MSC/HA (group C) and CBB/MSC (control group). Attachment and morphology of MSC were observed by scanning electronic microscope; the proliferation of MSC was evaluated by cell count; alkaline phosphatase(ALP) activity was examined by histochemistry and type I collagen synthesis was examined by immunohistochemistry staining 5 and 10 days later. RESULTS: In group A, MSC spread better, and ALP activity of group A was significantly higher than that of group B and control group(P lt; 0.01); but there was no significant difference between group A and group C(P gt; 0.05). There was no significant difference in type I collagen synthesis between four groups on the 5th day; but mean gray scale of type I collagen in group B was significantly higher than that in the other groups on the 10th day(P lt; 0.01). CONCLUSION: Different compound patterns of CBB, HG and MSC affect attachment, proliferation, differentiation of MSC. The compound pattern of CBB/HG/MSC is better than the others.
ObjectiveTo review the application of silk fibroin scaffold in bone tissue engineering. MethodsThe related literature about the application of silk fibroin scaffold in bone tissue engineering was reviewed, analyzed, and summarized. ResultsSilk fibroin can be manufactured into many types, such as hydrogel, film, nano-fiber, and three-dimensional scaffold, which have superior biocompatibility, slow biodegradability, nontoxic degradation products, and excellent mechanical strength. Meanwhile these silk fibroin biomaterials can be chemically modified and can be used to carry stem cells, growth factors, and compound inorganic matter. ConclusionSilk fibroin scaffolds can be widely used in bone tissue engineering. But it still needs further study to prepare the scaffold in accordance with the requirement of tissue engineering.
ObjectiveTo prepare of a novel functional self-assembling peptide nanofiber hydrogel scaffold RADKPS designed with linking the short functional motif of bone morphogenetic protein 7 (BMP-7) and to evaluate its biocompatibility so as to provide the experimental basis for in vivo studies on regeneration of degenerated nucleus pulposus tissue. MethodA functional self-assembling peptide RADA-KPSS was designed by linking the short functional motif of BMP-7 to the self-assembling peptide RADA16-I. And the novel functional self-assembling peptide RADKPS was finally prepared by isometric mixing RADA16-I with RADA-KPSS. The structure characteristic of the functional self-assembling peptide nanofiber hydrogel scaffold RADKPS was evaluated by general observation and atomic force microscopy. Bone marrow mesenchymal stem cells (BMSCs) were isolated from 3-month-old New Zealand white rabbits and cultured. After the 3rd generation BMSCs were seeded on the peptide nanofiber hydrogel scaffold RADKPS for 7 days, the cellular compatibility of RADKPS was evaluated through scanning electron microscopy assay, cellular fluorescein diacetate/propidium iodide staining, and MTT assay. 1%RADKPS was injected into isolated intervertebral disc organs from 6-month-old New Zealand white rabbits, then the organs were cultured and the cellular activity of the intervertebral disc organs was observed. The blood compatibility of RADKPS was evaluated with hemolytic assay. After RADKPS was implanted into subcutaneous part of Kunming mice (aged 6-8 weeks) for 28 days, general observation and HE staining were carried out to evaluate the tissue compatibility. ResultsThe functional self-assembling peptide solution RADKPS presented a homogeneous transparent hydrogel-like. Atomic force microscopy revealed that the RADKPS could self-assemble into three-dimensional nanofiber hydrogel scaffolds; the fibre diameter was (25.68±4.62) nm, and the fibre length was (512.42±32.22) nm. After BMSCs cultured on RADKPS for 7 days, scanning electron microscopy showed that BMSCs adhered to the scaffolds. And cell viability was maintained over 90%. MTT assay revealed that RADKPS of 0.1%, 0.05%, and 0.025% could increase the proliferation of BMSCs. The result of hemolytic assay revealed that the hemolysis rates of the RADKPS solutions with different concentrations were less than 5%, indicating that it met the requirement of hemolytic assay standard for medical biomaterials. After subcutaneous implantation, no vesicle, erythema, and eschar formation around injection site were observed. Meanwhile, HE staining showed inflammatory cells infiltration (lymphocytes), substitution of hydrogel scaffold by fibrous tissue, and good tissue compatibility. ConclusionsThe novel functional self-assembling peptide nanofiber hydrogel scaffold RADKPS has good biocompatibility and biological reliability, which would be suitable for tissue engineering repair and regeneration of nucleus pulposus tissue.
Objective To fabricate in situ crosslinking hyaluronic acid hydrogel and evaluate its biocompatibility in vitro. Methods The acrylic acid chloride and polyethylene glycol were added to prepare crosslinking agent polyethylene glycol acrylate (PEGDA), and the molecular structure of PEGDA was analyzed by Flourier transformation infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy. Hyaluronic acid hydrogel was chemically modified to prepare hyaluronic acid thiolation (HA-SH). And the degree of HA-SH was analyzed qualitatively and quantitatively by Ellman method. HA-SH solution in concentrations (W/V) of 0.5%, 1.0%, and 1.5% and PEGDA solution in concentrations (W/V) of 2%, 4%, and 6% were prepared with PBS. The two solutions were mixed in different ratios, and in situ crosslinking hyaluronic acid hydrogel was obtained; the crosslinking time was recorded. The cellular toxicity of in situ crosslinking hyaluronic acid hydrogel (1.5% HA-SH and 4% PEGDA mixed) was tested by L929 cells. Meanwhile, the biocompatibility of hydrogel was tested by co-cultured with human bone mesenchymal stem cells (hBMSCs). Results Flourier transformation infrared spectroscopy showed that most hydroxyl groups were replaced by acrylate groups; 1H nuclear magnetic resonance spectroscopy showed 3 characteristic peaks of hydrogen representing acrylate and olefinic bond at 5-7 ppm. The thiolation yield of HA-SH was 65.4%. In situ crosslinking time of hyaluronic acid hydrogel was 2 to 70 minutes in the PEGDA concentrations of 2%-6% and HA-SH concentrations of 0.5%-1.5%. The hyaluronic acid hydrogel appeared to be transparent. The toxicity grade of leaching solution of hydrogel was grade 1. hBMSCs grew well and distributed evenly in hydrogel with a very high viability. Conclusion In situ crosslinking hyaluronic acid hydrogel has low cytotoxicity, good biocompatibility, and controllable crosslinking time, so it could be used as a potential tissue engineered scaffold or repairing material for tissue regeneration.
ObjectiveTo study the growth of adipose-derived stem cells (ADSCs) planted in three-dimensional (3D) materials, a 3D cultured ADSCs system based on microbial transglutaminase (mTG) enzyme crosslinked gelatin hydrogel was constructed. MethodsADSCs were isolated from the subcutaneous adipose tissue of a Sprague Dawley rat by collagenase digestion and centrifugation, and were cultured for passage. The mTG enzyme crosslinked gelatin hydrogel was firstly synthesized by mixing gelatin and mTG, and then the ADSCs were encapsulated in situ (2D environment) and cultured in the 3D materials (3D environment). The morphology and adhesion of cells were observed by inverted phase contrast microscope. In addition, HE staining and Masson staining were carried out to observe the distribution of cells in the material. Living and death situation of ADSCs in the materials was observed by fluorescence microscope and laser scanning confocal microscopy. Scanning electron microscopy was used to observe the adhesion of ADSCs on hydrogel surface. Alamar-Blue method was used to detect the proliferation of ADSCs in the hydrogel. Moreover, the results were compared between the cells cultured in 2D environment and those in 3D environment. ResultsThe result of 2D culture showed that ADSCs grew well on the hydrogel surface with normal functioning and had good adhesion. The results of 3D culture showed that ADSCs grew well in 3D cultured mTG enzyme crosslinked gelatin hydrogel, and presented 3D shape. Cells obviously extended in all directions. The number of apoptotic cells was very small. The cells of 3D culture at each time point was significantly less than that of the conventional culture cells, difference was statistically significant (P < 0.05). But after 8 days culture, the proliferation of the cells cultured in the mTG enzyme crosslinked gelatin hydrogel increased more quickly. ConclusionADSCs can grow well with good adhesion and show high viability in 3D culture system constructed by mTG enzyme crosslinked gelatin hydrogel.
ObjectiveTo summarize the research progress of hydrogels for the regeneration and repair of degenerative intervertebral disc and to investigate the potential of hydrogels in clinical application.MethodsThe related literature about the role of hydrogels in intervertebral disc degeneration especially for nucleus pulposus was reviewed and analyzed.ResultsHydrogels share similar properties with nucleus pulposus, and it plays an important role in the regeneration and repair of degenerative intervertebral disc, which can be mainly applied in nucleus pulposus prosthesis, hydrogel-based cell therapy, non-cellular therapy, and tissue engineering repair.ConclusionHydrogels are widely used in the regeneration and repair of intervertebral disc, which provides a potential treatment for intervertebral disc degeneration.
Heart failure affects quality of life and life expectancy of tens of millions of individuals. There are no available economic and effective treatments for end-stage heart failure. Hydrogels are novel tissue engineering materials, which have the potential to ameliorate myocardium remodeling, increase cardiac output, improve quality of life and prolong life span by implantation into myocardium. The preclinical experiments and clinical trials have greatly explored the function of hydrogels in heart failure. In this review, we summarized the approaches of implantation, mechanism and clinical outcomes of the hydrogels.